Speech control of a medical apparatus

ABSTRACT

One or more example embodiments provides a method for speech control of a medical apparatus, the method comprising capturing an audio signal containing operator speech input directed at controlling the apparatus; first analyzing the audio signal for a first speech analysis result; recognizing a first speech command based on the first speech analysis result; assigning the first speech command to a safety class, the safety class being provided for safety-critical speech commands; ascertaining a verification signal to confirm the first speech command; generating a control signal for controlling the medical apparatus, the generating being based on the first speech command and the verification signal, wherein the control signal is for controlling the medical apparatus according to the first speech command; and inputting the control signal into the medical apparatus.

CROSS-REFERENCE TO RELATED APPLICATION(S)

The present application claims priority under 35 U.S.C. § 119 to European Patent Application No. 21198529.6, filed Sep. 23, 2021, the entire contents of which are incorporated herein by reference.

FIELD

One or more example embodiments relates to a method for speech control of a medical apparatus by processing an audio signal containing operator speech input directed at controlling the apparatus. One or more example embodiments relates to a method for first-failure safety speech control of a medical apparatus. The invention also relates to a corresponding medical system having a medical apparatus.

BACKGROUND

Medical apparatuses typically used to treat and/or examine and/or monitor a patient are for example, imaging modalities such as magnetic resonance apparatuses, computed tomography apparatuses, PET apparatuses (positron emission tomography apparatuses) or interventional and/or therapeutic apparatuses, such as radiation-emitting or radiotherapy apparatuses. The treatment and/or examination of the patient is typically supported by operating staff.

Before and during the treatment and/or examination of a patient with such a medical apparatus, usually various settings have to be made on the medical apparatus, such as, for example, inputting patient data, setting various device parameters and the like. These steps are performed by the medical staff, wherein the settings of the medical apparatus are typically made via a physical user interface provided on the apparatus into which an operator can make entries.

In order to operate such medical apparatuses economically, a smooth workflow or process flow is desirable. In particular, making settings should be as easy as possible. A speech control system in which an operator transfers control commands via a natural speech signal to the medical apparatus is particularly suitable for this purpose. In this regard, DE 10 2006 045 719 B4 describes a medical system with a speech input apparatus with which specific functions of the system can be activated and deactivated via speech control. Herein, an audio signal captured with the speech input apparatus is processed by a speech analysis module in order to ascertain speech commands from an operator.

For speech control, i.e., the analysis or recognition of a user intention or a speech command formulated via natural speech, it is preferable to use artificial intelligence algorithms, preferably neural networks. These are particularly well suited for imaging a high-dimensional input space comprising a plurality of different speech sequences corresponding to natural speech input onto a target space comprising a number of defined control commands.

For approval, many medical apparatuses also have to meet the requirement of first-failure safety or functional safety, in order to ensure the safety of patients and operating staff at all times during the increasingly automated operation of the medical apparatus. First-failure safety means that no single first error can have the result that the medical apparatus can become unsafe to use during its lifetime.

A particularly safety-critical control command is, for example, directed at releasing/starting X-radiation during image data capture or radiotherapy. Another example of a safety-critical control command relates to the (autonomous) adjustment movement of a medical apparatus or one of the components thereof, for example a robot arm, in space. Unauthorized or unconfirmed radiation release or apparatus movement can directly endanger the well-being of the patient or an operator.

In order to embody hardware and/or control software of a medical apparatus for processing and converting control commands captured via any user interface in a functionally safe or first-failure safe manner, it is customary to request manual authorization of a recognized control command from an operator. One example of this is a so-called dead man grip. This switch/lever/grip has to be continuously actuated by an operator in order to carry out an automatic adjustment movement on a medical apparatus. The adjustment movement stops automatically when the operator releases the dead man grip.

Alternatively, the medical apparatus can operate a second redundant software system on independent hardware, i.e., its own processor or own memory, to safeguard control software. The control command is only actually executed by the medical apparatus if the redundant software system checks the plausibility of the initially recognized control command, otherwise it is discarded.

In the field of speech control, there is currently still a fundamental lack of established and reliable methods for verifying the quality of speech recognition algorithms required for functional or first-failure safety. For example, the question of universal criteria that a training data set of a first-failure safety (AI) speech recognition algorithm (AI=artificial intelligence) must satisfy, or of a generally valid measure of robustness of an (AI) speech recognition algorithm for the correct classification of speech input that has been altered, for example, by distortion or background noise are the subject of current research. One approach based on existing safety standards for verifying a recognized speech command is also not sufficiently safe or not possible, since conventionally defined requirements/criteria for AI speech recognition algorithms are also missing here in order to prove their fulfillment. This would be a mandatory requirement for the approval or certification of (AI) speech recognition algorithms. In addition, the verification of a recognized speech command via an identical redundant speech recognition algorithm, which, in case of doubt, repeats the first failure, would not ensure first-failure safety.

SUMMARY

As a result, to date speech control of medical apparatuses has only been used outside of safety-critical applications.

One or more example embodiments solve this problem and provide means for speech control of a medical apparatus, which allows speech commands from an operator to be ascertained from an audio signal in an improved, i.e., more reliable, manner. For example, one or more example embodiments of the present invention provides means that ensure first-failure safety via speech control.

At least some example embodiments provide a method for speech control of a medical apparatus, a corresponding speech control apparatus, a medical system comprising the speech control apparatus, a computer program product and a computer-readable storage medium.

According to one or more example embodiments, a method for speech control of a medical apparatus includes capturing an audio signal containing operator speech input directed at controlling the apparatus; first analyzing the audio signal for a first speech analysis result; recognizing a first speech command based on the first speech analysis result; assigning the first speech command to a safety class, the safety class being provided for safety-critical speech commands; ascertaining a verification signal to confirm the first speech command; generating a control signal for controlling the medical apparatus, the generating being based on the first speech command and the verification signal, wherein the control signal is for controlling the medical apparatus according to the first speech command; and inputting the control signal into the medical apparatus.

According to one or more example embodiments, the ascertaining the verification signal includes the first speech command and the method further comprises issuing a prompt to confirm the first speech command to the operator.

According to one or more example embodiments, the ascertaining the verification signal comprises capturing user input directed at the confirmation of the first speech command from the operator.

According to one or more example embodiments, at least one of the outputting outputs an audio signal based on the speech command, or the capturing captures the user input as an audio signal.

According to one or more example embodiments, the verification signal confirms the first speech command if the operator the user input satisfies at least one of a predefined time criterion, or a predefined content criterion.

According to one or more example embodiments, the time criterion is adjustable based on the first speech command.

According to one or more example embodiments, the ascertaining the verification signal comprises outputting a prompt for the user input to the operator and capturing the user input, the user input comprising the speech control information.

According to one or more example embodiments, the first analyzing comprises applying a first computational linguistics algorithm, the first computation linguistics algorithm comprising a first trained function to the audio signal.

According to one or more example embodiments, the ascertaining the verification signal comprises analyzing the audio signal to provide a second speech analysis result, recognizing a second speech command based on the second speech analysis result, and comparing the first and second speech command, wherein the verification signal confirms the first speech command if the first speech command and the second speech command satisfy a conformity criterion.

According to one or more example embodiments, the first analyzing comprises applying a second computational linguistics algorithm, the second computational linguistics algorithm comprising a second trained function to the audio signal, wherein the first trained function and the second trained function are different from one another.

According to one or more example embodiments, the second trained function is configured only to identify safety-critical speech commands in the audio signal.

According to one or more example embodiments, the first analyzing the audio signal comprises at least one of tokenizing for at least one of segmenting letters, words or sentences within the audio signal, and at least one of the first speech command or the second speech command are recognized based on at least one of first tokenization information or second tokenization information, or recognizing semantic analysis of the audio signal and the first speech command and the second speech command are recognized based on first semantic information and second semantic information.

According to one or more example embodiments, a speech control apparatus for speech control of a medical apparatus comprises at least one first interface configured to capture an audio signal containing operator speech input directed at controlling the apparatus; at least one evaluation unit configured to analyze the audio signal and provide a first speech analysis result, recognize a first speech command based on the first speech analysis result, assign the first speech command to a safety class, wherein a safety class is provided for safety-critical speech commands, ascertain a verification signal to confirm the first speech command; a control unit configured to generate a control signal for controlling the medical apparatus based on the first speech command and the verification signal provided that the first speech command has been based on the verification signal, wherein the control signal is suitable for controlling the medical apparatus according to the first speech command; and a second interface configured to input the control signal into the medical apparatus.

According to one or more example embodiments, a medical system comprises the speech control apparatus and the medical apparatus.

According to one or more example embodiments, a non-transitory computer program product, which comprises a program and can be loaded directly into a memory of a programmable computing unit, has program means for executing a method according to one or more example embodiments.

According to one or more example embodiments, a non-transitory computer-readable storage medium stores readable and executable program that, when executed by a programmable computing unit, cause the programmable computing unit to perform the method of claim 1.

BRIEF DESCRIPTION OF THE DRAWINGS

Features and advantages of example embodiments of the present invention will become apparent from the following explanations of exemplary embodiments with reference to schematic drawings. Modifications mentioned in this context can in each case be combined with one another in order to form new embodiments. The same reference figures are used for the same features in different figures.

FIG. 1 illustrates a schematic block diagram of a system for controlling a medical apparatus according to one embodiment,

FIG. 2 illustrates a block diagram of a system for controlling a medical apparatus according to a further embodiment,

FIG. 3 illustrates a schematic flow diagram of a method for controlling a medical apparatus according to one embodiment,

FIG. 4 illustrates a further schematic flow diagram of a method for controlling a medical apparatus according to one embodiment,

FIG. 5 illustrates an alternative schematic flow diagram of a method for controlling a medical apparatus according to one embodiment, and

FIG. 6 illustrates a neural network of a computational linguistics algorithm according to the invention in one embodiment.

DETAILED DESCRIPTION

The following describes the achievement of the object according to one or more example embodiments of the present invention with respect to the claimed method and with respect to the claimed apparatuses. Features, advantages or alternative embodiments are likewise applicable to the other claimed subject matter and vice versa. In other words, physical claims (which are, for example, directed at a speech control apparatus) can also be developed with features described or claimed in connection with a method. Here, the corresponding functional features of the method are embodied by corresponding physical features, for example modules or units, of one of the apparatuses.

In a first aspect, the present invention relates to a method for speech control of a medical apparatus. In some embodiments, the method is embodied as a computer-implemented method. The method comprises a plurality of steps.

One step is directed at capturing an audio signal containing operator speech input directed at controlling the apparatus. One step is directed at analyzing the audio signal for providing a first speech analysis result. One step is directed at recognizing a first speech command based on the first speech analysis result. One step is directed at assigning the first speech command to a safety class for the first speech control command, wherein at least one safety class is provided for safety-critical speech commands. One step is directed at ascertaining a verification signal to confirm the first speech command.

This step is preferably executed if the first speech command was assigned to the safety class for safety-critical speech commands. In some embodiments of the present invention, safety-critical speech commands comprise speech commands for the medical apparatus that in particular must be embodied as first-failure safe.

One step is directed at generating a control signal for controlling the medical apparatus based on the first speech command and the verification signal. This step is executed provided that the first speech command has been confirmed based on the verification signal. Herein, the control signal is suitable or embodied to control the medical apparatus according to the first speech command. A further step is directed at inputting the control signal into the medical apparatus.

For the purposes of the invention, an audio signal can in particular contain sound information. The audio signal can be an analog or digital or digitized signal. The digitized signal can be generated based on the analog signal, for example by an analog-to-digital converter. Accordingly, the step of capturing can comprise providing a digitized audio signal based on the received audio signal or digitizing the received audio signal. In some embodiments, the capturing of the audio signal can comprise registration of the audio signal via a suitable sensor, for example an acoustic sensor in the form of a microphone, which can be a component of a user interface of the medical apparatus. The capturing of the audio signal can furthermore comprise providing the digital or digitized signal for further analysis steps.

The audio signal can comprise a communication from a user (hereinafter also operator), for example an instruction to be executed or information regarding the instruction to be executed, for example speech control information. In other words, the audio signal can comprise operator speech input in natural speech. Natural speech is typically speech spoken by humans. Natural speech can include intonation and/or inflection to modulate communication, unlike formal speech, natural speech can include structural and lexical ambiguities.

For the purposes of one or more example embodiments of the present invention, analysis of an audio signal is directed at inferring or recognizing content of the operator speech input. The analysis can comprise recognizing a human voice. The analysis can comprise analyzing values of the speech input, such as, for example, frequency, amplitude, modulation or the like, which are characteristic of human speech. The result of the analysis is at least partially provided in the form of a speech analysis result.

The analysis according to one or more example embodiments of the present invention can apply a method for processing natural speech. In particular, according to the first aspect of one or more example embodiments of the present invention, a first computational linguistics algorithm can be applied to the audio signal or the speech input. One possibility for processing speech input formulated in natural speech to provide the speech analysis result is to convert the speech input formulated in natural speech into text, i.e., into structured speech via a speech-to-text (software) module. Subsequently, a further analysis for providing the speech analysis result, for example via latent semantic analysis (or latent semantic indexing, LSI), can assign meaning to the text. In particular, herein, the audio signal is analyzed as a whole. Herein, it can be provided that individual words or word groups and/or syntax are recognized. The relationship/position of words or word groups to words or word groups appearing previously or later in the audio signal can also be taken into account. The analysis of the audio signal can in particular comprise a grammatical analysis, for example using a language or grammar model. Additionally or alternatively, the operator's inflection can be evaluated. In this way, one or more example embodiments of the present invention realizes understanding of the natural speech contained in the speech input (also called natural language understanding, NLU).

The step of recognizing a first speech command based on the first speech analysis result is directed at using the speech analysis result to assign a unique speech command to the meaning of the comprised text recognized in the speech input or to associate it with a predefined set of possible speech commands. Herein, in the step of recognizing the first speech command based on the speech analysis result, any number of different speech commands can be assigned to the speech input. Herein, each speech command is representative of an instruction for executing a work step, a defined action, operation or movement that is automatically executed by the medical apparatus based on the speech command. The recognition of the first speech command can comprise classification of the speech input based on the speech analysis result into a command class of a predefined set of different command classes. The predefined set of possible command classes can, for example, be present in the form of a command library. In particular, a plurality of speech input types that differ from one another or the individual speech analysis results thereof can be assigned to the same command class and thus to the same speech command according to their meaning.

In this way, the dimensionality of natural speech is taken into account in which inter alia one and the same user intention can be expressed via a different choice of words or inflection.

The command library can also comprise a command class for unrecognized speech commands which is assigned whenever the audio signal includes acoustic features which are non-specific to a concrete speech command or cannot be assigned to another command class.

The step of recognizing the first speech command can also be executed by applying the first computational linguistics algorithm. Herein, the step of recognizing the first speech command preferably follows the creation of a transcript (structured speech) of the speech signal or creation of a semantic analysis result based on the transcript. Both can be comprised in the first speech analysis result.

In some implementations, the large number of command classes is at least partially specific to the medical apparatus and is in particular directed at the functionality provided for the medical apparatus. In some implementations, the large number of command classes is embodied as adjustable and can in particular be adjusted via the selection or configuration or training of the computational linguistics algorithm used in the analysis. For example, further command classes can be added.

According to one or more example embodiments of the present invention, each command class or each speech command is assigned to a safety class. In each case, a safety class stands for a safety measure or safety level, which must be observed by the medical apparatus when executing the work step, operation or action corresponding to the respective speech command. Herein, the respective safety measure can be a safety measure defined via standardization. According to one or more example embodiments of the present invention, at least two safety classes are provided. The two safety classes divide the speech commands or the command classes thereof into safety-critical speech commands comprising first-failure safety speech commands and non-safety-critical speech commands. Advantageously, more than two safety classes are provided in each case corresponding to different safety levels or safety stages. Here, once again, at least one safety class is provided for safety-critical speech commands comprising first-failure safety speech commands, wherein further command classes can be provided for safety-critical speech commands, wherein the safety requirements for ensuring the safety requirements can be of different levels depending on a command class. The safety requirements are highest for the command class comprising the first-failure safety speech commands.

In some implementations, a command class is assigned to a safety class based on a predefined assignment rule that takes into account the type of speech command or a degree of risk of the operation or action or movement of the medical apparatus to be triggered by the speech command to the patient and/or the operating staff and/or the medical apparatus or to other medical equipment. In some implementations, the assignment takes place via a predetermined lookup table. In further implementations, predefined keywords can be provided which can be recognized by the first computational linguistics algorithm in the audio signal and which are in each case linked to one of the safety classes. Herein, one or more keywords can be assigned to a safety class. In some embodiments, therefore, a safety class is assigned to the first speech command if one or more keywords have been recognized by the computational linguistics algorithm in the audio signal. Alternatively, the safety class can be automatically defined by a predefined assignment rule when the first speech command is recognized.

Consequently, the step of assigning the first speech command to a safety class is directed at identifying the first speech command as a safety-critical speech command, in particular as a first-failure safety speech command, or non-safety-critical speech command. In some implementations, this step is also executed by the first computational linguistics algorithm.

If the first speech command is recognized as a safety-critical speech command, in a further step, a verification signal is ascertained to confirm the first speech command. In this step, it is checked whether the first identified speech command actually corresponds to the user intention desired by the operator or the desired command. Herein, the verification signal indicates a measure for the conformity between the desired user intention and the first speech command. In some implementations, the verification signal can comprise verification information. The verification information can assume at least two discrete values, for example ‘1’ for complete conformity and ‘0’ for no conformity, in some embodiments also a plurality of different discrete values, for example between ‘1’ and ‘0’. Some of the discrete values can correspond to different conformity levels, which in each case can correspond to a proportional incomplete conformity. In some embodiments of the invention, these values can correspond to a sufficient conformity between the speech command and the desired user intention provided that the respective speech command is assigned a correspondingly low safety level according to one of the possible safety classes.

According to one or more example embodiments of the present invention, the verification signal is provided for further processing, for example to a control unit of a speech control apparatus according to one or more example embodiments of the present invention. In this respect, the step of generating a control signal based on the verification signal and the first speech command can comprise providing the same. The verification signal indicates whether or not the conformity measure required for the first speech command has been achieved.

If the first speech command is correspondingly confirmed via the verification signal, in a subsequent step, a control signal for controlling the medical apparatus is generated based on the first speech command and the verification signal and input into the medical apparatus.

With the step of ascertaining the verification signal, the present invention advantageously applies monitoring or plausibility checking of a speech command, i.e., of a control command obtained via methods of machine speech analysis. In other words, with these steps, the present invention, enables the implementation of a test (P-protect) path for speech commands according to a first-failure safety system. If the first speech command is confirmed by the plausibility checking step (verification signal shows conformity), the first speech command is further processed and executed by the medical apparatus. If the first speech command is not confirmed by the plausibility checking step (verification signal shows a discrepancy), the process is aborted and the first speech command is discarded and not executed.

With the ascertaining of the verification signal, one or more example embodiments of the present invention advantageously makes it possible to prevent the execution of user input that has been incorrectly recognized or incorrectly interpreted via machine speech recognition. In particular, in this way the safety-critical or first-failure safety execution of control commands is ensured. The first speech command recognized is only executed if it has been confirmed via the plausibility checking step.

In some embodiments of the invention, the verification signal is implemented in a separate independent hardware and/or software system. In particular, therefore, the verification signal is ascertained independently of the previous process steps. Algorithms for ascertaining the verification signal in particular differ from the computational linguistics algorithms previously used in the method. In some embodiments of the invention, the step of ascertaining the verification signal is executed in another real or virtual computing unit than the previous process steps. As a result, according to one or more example embodiments of the present invention, a first-failure safety system comprising a control path (C-path, C-control) and a test path (P-path, P-protect) can be set up wherein the step of ascertaining the verification signal takes place within the P-path. In particular, the steps of capturing an audio signal containing operator speech input directed at controlling the apparatus, first analysis of the audio signal for providing a first speech analysis result, recognizing a first speech command based on the first speech analysis result and assigning the first speech command to a safety class, wherein a safety class is in particular provided for first-failure safety speech commands, form an essential part of the C-path.

According to one or more example embodiments of the present invention, the step of ascertaining the verification signal can be executed in various ways, as described in more detail below.

On the one hand, ascertaining the verification signal can comprise capturing and evaluating further user input. In this embodiment, the first speech command is confirmed based on this user input. Alternatively or additionally, the ascertaining can comprise a further second machine speech analysis that is independent of the first analysis of the audio signal, wherein a second speech command is derived. Here, the confirmation of the first speech command is derived based on a comparison of the first and second speech command.

According to some implementations of one or more example embodiments of the present invention, ascertaining the verification signal comprises outputting the first speech command and a prompt to confirm the first speech command to the operator. The output of the first speech command to the operator serves to let the operator know which speech command was automatically recognized by machine as the first speech command based on the analyzed speech input.

In addition, the output comprises a prompt to confirm the first speech command by user input. In other words, in implementations based on the first recognized speech command, at least one corresponding control signal for an output apparatus, in particular an acoustic output apparatus, of a user interface of a speech control apparatus according to one or more example embodiments of the present invention or a medical apparatus is generated based on which the output unit generates output data.

According to further implementations of one or more example embodiments of the present invention, ascertaining the verification signal also comprises capturing user input. This is directed at the confirmation of the first speech command by the operator. If the first speech command output is recognized by the operator as the speech command that conforms to the desired command, the operator can issue confirmation corresponding to the prompt output which can be registered and further processed as user input via an input unit of the user interface of the medical apparatus, in particular via an evaluation unit (or a submodule thereof) of the speech control apparatus.

Particularly preferably, in some embodiments of the invention, the outputting comprises outputting an audio signal based on the first speech command, and/or the capturing comprises capturing user input embodied as an audio signal. In other words, in some embodiments, the plausibility checking step of the method according to the invention is also executed with machine speech processing means or algorithms in which an audio signal is generated in the form of natural speech in a substep.

According to some implementations of one or more example embodiments of the present invention, therefore, based on the first recognized speech command, an algorithm for speech generation is applied to generate an audio signal comprising natural speech (also called natural language generation, NLG). Therefore, text-to-speech conversion takes place. In some embodiments, the generation of speech from (structured) text can be executed via a further computational linguistics algorithm which acts inversely to a first computational linguistics algorithm. In some embodiments, the audio signal can comprise outputting the audio signal via a suitable sound transducer, for example a loudspeaker, which can also be part of a user interface.

In some implementations of one or more example embodiments of the present invention, the user input is also made as speech input and a corresponding audio signal is captured. Therefore, the user input can take place in the form of an audio signal and comprises natural speech, as described above, and a tone of voice and/or an inflection to modulate the communication. Therefore, the user input can also contain sound information and be an analog or digital or digitized signal. The digitized signal can be generated based on the analog signal, for example by an analog-to-digital converter and the capturing can comprise providing a digitized audio signal based on the received audio signal or digitization of the received audio signal. In some embodiments, the capturing of the user input can take place via the user interface microphone described in the introduction.

The captured user input is then analyzed in order to infer its content. Here, once again, as described in the introduction, the analysis comprises an analysis of values of the speech input, such as, for example, frequency, amplitude, modulation or the like, which are characteristic of human speech. The analysis can also take place via a further computational linguistics algorithm, which can be embodied as already described above. In some embodiments, this further computational linguistics algorithm can be embodied to recognize, in particular short, keywords, directed at confirming a command, such as ‘Yes’, ‘Confirmed’, ‘Check’ or the like.

In alternative implementations of one or more example embodiments of the present invention, the output of the first speech command and the capture of the confirmatory user input can be embodied differently. For example, the first speech command can alternatively take place via a graphical display, which can also be part of the user interface. This embodiment comprises a corresponding conversion of the first speech command into control signals or graphical output data for the display. In further implementations, the capture of the user input can comprise machine recognition of an operator gesture or the registration of the push of a button or touch on a display embodied as a touch display. Accordingly, capture of the user input comprises respective recognition or registration of the user input via an optical sensor (such as, for example, a camera), a resistive or capacitive sensor or a pressure sensor or force sensor or the like and conversion of the signal captured in each case into an electrical signal that can be further processed.

Further variants are possible in which in particular in each case acoustic output of the first speech command or acoustic capture of the user input directed at the confirmation can in each case be combined with differently embodied output or capture variants.

In preferred implementations of one or more example embodiments of the present invention, the verification signal confirms the first, recognized speech command if the operator user input satisfies

-   -   a predefined time criterion         and/or     -   a predefined content criterion.

In other words, the method according to one or more example embodiments of the present invention runs through a test step in which the user input must satisfy at least an expectation in terms of content or expectation in terms of time. In preferred implementations, the content criterion and/or time criterion are dependent upon the first recognized speech command or the safety class assigned thereto. In the case of a control command which, if executed unintentionally by the medical apparatus, poses a high risk in particular for the patient or operator, according to one or more example embodiments of the present invention, the user input directed at the confirmation will have to satisfy a stricter time criterion than a control command which poses a lower risk in the event of unintentional execution.

In some embodiments, a time criterion can correspond to a temporal threshold value or a time period defined in advance according to a respective speech command or a command class within which the user input must take place. For example, a lower time threshold value is assigned to a speech command of a higher safety level/safety class than to a speech command of a low safety level. This approach is based on the consideration that confirmation of a speech command that has been correctly recognized and conforms to the desired user intention can take place almost instantaneously or very quickly and a delay in confirmation in areas above the temporal threshold value typically indicates at least uncertainty with respect to the first speech command on the part of the operator or even a discrepancy between the desired user intention and the first recognized speech command. Therefore, if the user input does not take place within the specified time period or after a time period defined as an abort criterion, the first speech command is discarded and not executed.

In some implementations, one or more example embodiments of the present invention can also comprise outputting the prompt to confirm the first speech command and also the corresponding time period according to the time criterion in which the user input must take place.

In preferred embodiments of the invention, a content criterion is provided in which the user input directed at the confirmation is made in the form of an audio signal or content analysis takes place with respect to the user input. A content criterion can in particular be present in the form of one or more keywords or word sequences which are dependent on the respective control command or its safety class and are defined in advance. If these are recognized via the further computational linguistics algorithm applied to the user input, the content criterion is satisfied. If the keywords are not recognized, the first speech command is discarded and not executed by the medical apparatus.

In some embodiments of the invention, a content criterion can, for example, also consist in the fact that a predefined pressure or force threshold value is reached or exceeded at a corresponding sensor of the operator interface. Accordingly, in preferred implementations of one or more example embodiments of the present invention, it can be provided that the output of the prompt to confirm the first speech command also comprises an indication of how, for example with which keywords or with which pressure, the confirmatory user input must take place.

In particular, for speech commands with a high safety level, validation of the first speech command can require the satisfaction of a content criterion and a time criterion so that the first speech command can be executed. In particular, in some embodiments of the invention, a time period can be selected for the time criterion such that it takes account of an expected length of user input in the form of speech input.

The checking of the content and/or time criterion is followed by the generation of the verification signal, which, depending on the result of the check, comprises verification information, which, for example, assumes a predefined discrete value, for example ‘1’ in the case of complete conformity between the desired user intention and the first speech command.

In some embodiments of the invention, the step of ascertaining a verification signal is implemented in the conventional manner. Therefore, monitoring of the content and/or time criterion can be verified using conventional methods and is resilient in terms of safety, although the verification signal is also based on a control command in the form of the first speech command generated via machine speech analysis, i.e., via a software component that is not resilient in terms of safety. Resilience is in particular ensured by the predefined time and content safety criteria. In this way, the present invention reduces the probability of an incorrectly recognized speech command actually being executed by the medical apparatus.

In further implementations of one or more example embodiments of the present invention, the time criterion is embodied as adjustable in dependence on the first speech command. Consequently, in some embodiments, the method according to the invention can comprise an adjustment step in which the time criterion can be adjusted or changed based on, for example, user-specific specifications or user input.

In other words, a temporal threshold value that was predefined for the validation of the first speech command, for example based on empirical values can be (subsequently) adjusted, in particular enlarged. This gives the operator greater flexibility when issuing the confirmation. As a result, the operator has more time to confirm the first speech command. This approach results in greater user friendliness and thus acceptance of the technical solution in everyday medical practice, in particular if the operator is responsible for the entire medical workflow and patient monitoring. The adjustment of the temporal criterion can in particular be provided for speech commands assigned to a lower safety level. Alternatively or additionally, a value range for a permissible time period for the time criterion can be stored for each of the command classes. In these embodiments, the time criterion can only be adjusted within the value range.

In further embodiments, it can be provided for certain speech commands, in particular speech commands with a high safety level, that the operator must enter confirmatory user input several times, wherein each user input can be assigned a content and/or temporal criterion, which must be satisfied in each case in the sense of confirmation of the first speech command. Accordingly, ascertaining the verification signal can comprise a plurality of, for example two or three, confirmation cycles.

Accordingly, ascertaining the verification signal can comprise multiple outputs of a prompt embodied as described above to confirm the first speech command to the operator, i.e., one prompt for each confirmation cycle. Alternatively or additionally, ascertaining the verification signal can comprise multiple captures of confirmatory user input with the above-described means, i.e., one capture for each confirmation cycle.

In some embodiments of the invention, the number of confirmation cycles can also be embodied as adjustable taking into account the respective speech command or its safety level.

In this way, the method according to one or more example embodiments of the present invention is scalable and can be modified according to a user preference with regard to greater ease of operation (fewer confirmation cycles and/or larger time thresholds) and/or higher safety (more confirmation cycles and/or smaller time thresholds). Thus, the scalability of the teaching according to one or more example embodiments of the present invention can contribute to greater resilience in terms of safety of the validation of the first speech command according to a conventional P-path.

Further implementations of one or more example embodiments of the present invention provide that ascertaining the verification signal also comprises outputting a prompt for user input of speech control information specific to the recognized speech command to the operator and capturing the user input comprising the speech control information.

Capturing specific speech control information is particularly well-suited for controlling the medical apparatus via speech because the operator's hand is not needed for this. The hand can advantageously remain on the patient, for example. In addition, specific speech control information can be input simultaneously or directly together with the confirmation of the first speech command which facilitates operation overall.

The output of the prompt for user input of the speech control information is preferably dependent on the first speech command. For example, a predefined data stream representing the prompt to input speech control information can be stored for a speech control command or each command class2, in each case an audio signal comprising natural speech is generated from the text contained in the data stream via the above-described algorithm for speech generation (NLG). Speech control information is an indication or information required for the conversion of the first speech command. The speech control information can, for example, relate to the setting of one or more operating parameters of the medical apparatus, for example the speech control information can indicate the length of a travel path for an adjustment movement of the medical apparatus or the like. Accordingly, the further computational linguistics algorithm can be embodied to analyze user input comprising the speech control information and to identify the speech control information.

For this purpose, the further computational linguistics algorithm can again be embodied to recognize keywords or numbers, for example ‘5 mm’ or the like.

In further preferred implementations of one or more example embodiments of the present invention, the analysis of the audio signal comprises applying a first computational linguistics algorithm comprising a first trained function to the audio signal, i.e., a trained machine learning algorithm. Preferably, the recognition of a first speech command based on the first speech analysis result and the assignment of the first speech command to a safety class also comprise applying the first computational linguistics algorithm.

Preferably, the trained function or the trained machine learning algorithm comprises a neural network, preferably a convolutional neural network. A neural network is substantially structured like a biological neural network, for example like the human brain. Preferably, an artificial neural network comprises an input layer and an output layer. In between, it can comprise a large number of intermediate layers. Each of the layers comprises a number, preferably a large number, of nodes. Herein, each node is considered to be a biological computing unit or switching point, for example a neuron. In other words, a single node corresponds to a specific computing operation applied to the input data. Nodes in one layer can be connected to one another via corresponding edges or connections and/or to nodes in other layers, especially via directed connections. These edges or connections define the network data flow. In preferred embodiments, an edge/connection is equipped with a parameter, wherein the parameter is also referred to as a “weight”. This parameter regulates the influence or weight of the output data of a first node for the input of a second node that is in contact with the first node via the connection.

According to some embodiments of the invention, the neural network is a trained network. The training of the neural network is preferably performed in the sense of ‘supervised learning’ based on training data of a training data set, namely known pairs of input and output data. Herein, the known input data is passed as input data to the neural network and the output data of the neural network is compared with the known output data of the training data set. The artificial neural network now learns independently and adjusts the weights of the individual nodes or connections in such a manner and for such a time until the output data in the output layer of the neural network is sufficiently similar to the known output data of the training data set. In this context, in the case of convolutional neural networks, reference is also made to ‘deep learning’. The terms ‘neural network’ and ‘artificial neural network’ can be understood to be synonyms.

According to the invention, in some embodiments, the convolutional neural network, i.e., the trained function of the first computational linguistics algorithm, is trained in a training phase to analyze the captured audio signal and to recognize a first speech command or a command class according to the first speech command therefrom. The first speech command and/or the command class then corresponds to the output data of the trained function. In other embodiments of the invention, the trained function can also be trained to assign a safety class to the first speech command. The output data of the trained function of the first computational linguistics algorithm can then also comprise the safety class. Speech commands corresponding to the group of control commands to be recognized by the first computational linguistics algorithm can have a large number of feature combinations, i.e., a large number of different frequency patterns, amplitudes, modulations, or the like. Accordingly, in the training phase, the trained function learns to assign one of the possible speech commands or to classify the audio signal according to one of the command classes or to classify the audio signal according to a safety class based on a feature combination extracted from the audio signal in the sense of the first speech analysis result. The training phase can also comprise manual assignment of training input data in the form of speech input to individual speech commands or command classes.

A first group of neural network layers can be directed at extracting or ascertaining the acoustic features of an audio signal, i.e., the provision of the speech analysis result comprising a combination of acoustic features specific to the audio signal. The speech analysis result can be provided in the form of an acoustic feature vector. In this respect, a speech data stream, preferably comprising the audio signal in its entirety, is used as input data for the neural network. The speech analysis result can be used as input data for a second group of neural network layers, also referred to as the ‘classifier’. The second group of neural network layers is used to assign at least one speech command or command class to the extracted feature vector. Herein, the set of command classes can in particular also comprise a command class for non-recognized speech commands. Accordingly, the neural network can be trained to assign the audio signal to this class if no speech command can be uniquely recognized based on the features. A third group of neural network layers can be embodied to assign a safety class based on the command class and/or the recognized speech command, wherein in particular the ascertained command class and/or the recognized speech command are used as input data for the third group of neural network layers. The third group is now embodied to classify the command class and/or the recognized speech command as a safety-critical command, in particular as a first-failure safety command or non-safety-critical command.

The analysis steps or functions can also be executed by a plurality of, in particular two or three, independent neural networks. Consequently, the first computational linguistics algorithm can comprise one or more neural networks. For example, feature extraction can be executed with a first neural network and classification with a second neural network.

The classification of an audio signal into a command class based on the first speech analysis result can be based on a comparison of the extracted feature vector of the audio signal with feature vectors stored in the command library that are specific to each command class. One or more feature vectors can be stored for a command class in order to account for the multidimensionality of human speech and to be able to identify a concrete speech command based on a large number of different types of speech input.

The comparison of the feature vectors can comprise an individual comparison of individual features, preferably all features, comprised by the feature vectors. Alternatively or additionally, the comparison can be based on a feature parameter derived from the feature vector that takes account of individual features. The conformity measure for the feature vectors or feature parameters resulting from the comparison indicates which speech command or which command class is assigned. The command class that has the greatest similarity or a similarity above a defined threshold value is assigned.

The threshold value for the defined similarity measure can be preset automatically or by an operator. It can furthermore depend on the specific feature combination recognized for the audio signal. The threshold value can represent a large number of individual threshold values for individual features of the feature vector or a universal threshold value taking into account the large number of individual features comprised in the feature vector.

In preferred embodiments of the invention, a further computational linguistics algorithm for the analysis of the confirmatory user input in the form of an audio signal can also be embodied as further trained function, i.e., a further trained machine learning algorithm. As described with reference to the first trained function, in particular with a first group of neural network layers that use a data stream corresponding to the audio signal directed at the confirmation as input data, the further trained function can be trained to extract acoustic features such as frequency, amplitude, modulation or the like and, for example, provide them in the form of a further acoustic feature vector in particular to a second group of neural network layers. The further trained function can furthermore be trained to derive keywords or command triggers from the feature vector, in particular with the second group of neural network layers. Therefore, the second group of neural network layers is used to assign a unique keyword to the acoustic feature vector. For this purpose, a small set of keywords can be stored with respect to a recognized speech command or a command class, for example one or two keywords that must be recognized for confirmation of a speech command, for example exactly one keyword can be stored, in particular if the (acoustic) output of the prompt to confirm the first speech command also comprises an indication of how, for example with which keyword, the confirmation should take place, or also two or three keywords or a sequence of words.

Keywords are in particular short words or word sequences with a maximum of three or four syllables. Specific acoustic feature vectors can also be stored for the keywords of the individual command classes. Accordingly, the neural network of a further computational linguistics algorithm can be trained, in particular via the second group of neural network layers, to perform a comparison between the feature vector extracted from the audio signal directed at the confirmation and the stored feature vectors corresponding to the keywords assigned in each case. Herein, the comparison can be executed as already described with reference to the first trained function. If a keyword is recognized in an audio signal directed at the confirmation of the first speech command and thus satisfies a prespecified content criterion, a verification signal indicating this conformity is generated, as described in the introduction. The verification signal can furthermore comprise additional speech control information directed at the first confirmed speech command provided that this has been requested and entered by the operator. If the further trained function does not ascertain conformity with one of the stored keywords (content criterion not satisfied), a verification signal indicating that the first speech command has not been confirmed is generated.

Whereas the first trained function is trained to recognize a set of audio signals that is as broad and diverse as possible as a speech command on a predefined, in particular large, set of command classes, the further trained function is trained to identify a few keywords in audio signals.

Otherwise, reference is made to the description of the first trained function for the further trained function.

In further particularly preferred embodiments of the present invention, ascertaining the verification signal comprises the following:

-   -   analyzing the audio signal to provide a second speech analysis         result,     -   recognizing a second speech command based on the second speech         analysis result,     -   comparing the first and second speech command, wherein the         verification signal confirms the first speech command if the         first speech command and the second speech command satisfy a         conformity criterion.

In this embodiment, the audio signal is analyzed a second time, in particular independently of the first analysis step in order to generate a second speech analysis result in order to provide a second speech command based thereon, which is then compared with the first speech command. Therefore, in some embodiments of the invention, the steps directed at deriving the second speech command and comparing the first and second speech command also form a P-path that advantageously does not require any further user interaction. The steps directed at deriving the second speech command and comparing the first and second speech command can take place at least partially parallel in time with the derivation of the first speech command. For example, the captured audio signal can be supplied to the first and second analysis step at the same time. Alternatively, these steps for ascertaining the second speech command can be performed at a time after the derivation of the first speech command, then in particular triggered by the assignment of the first speech command to the safety class comprising the first-failure safety speech commands or another safety class with a high safety level.

Therefore, in an advantageous embodiment, the verification signal can be based on a comparison between the first and second speech command. If conformity is ascertained between the first and second speech command or the command classes assigned in each case, verification information confirming the first speech command is generated for the verification signal. Herein, ascertaining conformity between the first and second speech command corresponds to a test step or confirmation cycle according to one or more example embodiments of the present invention.

Additionally, in some embodiments of the invention, further confirmation cycles can be provided. Accordingly, it can be provided that, in addition to automatically ascertaining the conformity between the first and second speech command, it is necessary for at least one confirmation cycle to be run through, as described above, in which an operator is preferably prompted via automatic speech output to make a confirmatory user input in order to verify the first or second speech command as the desired command.

Therefore, in some embodiments, the verification signal is based on the satisfaction of a conformity criterion by the first and second speech command and, if applicable, the satisfaction of a content and/or time criterion. These implementations are particularly suitable for speech commands with high safety levels.

According to a preferred embodiment, the (second) analysis comprises applying a second computational linguistics algorithm comprising a second trained function to the audio signal. Preferably, the recognition of the second speech command based on the second speech analysis result also comprises applying the second computational linguistics algorithm. The first and second trained function are different trained functions according to one or more example embodiments of the present invention.

In some implementations, the second trained function is specifically embodied only to identify safety-critical speech commands in the audio signal. In this sense, in preferred embodiments, the second trained function or the second computational linguistics algorithm is specific to the speech commands of the safety-critical safety class comprising the first-failure safety speech commands.

The analysis with the second computational linguistics algorithm can also apply a method for processing natural speech. The second computational linguistics algorithm can be applied to the audio signal or the speech input. Herein, the speech input formulated in natural speech can be converted into text, i.e., into structured speech, to provide the second speech analysis result via a speech-to-text (software) module. Then, a further analysis for providing the second speech analysis result, for example via latent semantic analysis (also called latent semantic indexing, LSI) can assign meaning to the text. Here, the audio signal is again analyzed as a whole. It can also comprise the recognition of individual words or word groups and/or syntax. The relationship/position of words or word groups to words or word groups that appear previously or later in the audio signal can also be taken into account. In this way, one or more example embodiments of the present invention realizes understanding of the natural speech contained in the speech input (also called natural language understanding, NLU).

The step of recognizing the second speech command based on the second speech analysis result is also directed at assigning a unique speech command to the meaning of the comprised text recognized in the speech input or associating it with a predefined set of safety-critical speech commands, in particular first-failure safety speech commands. Herein, each safety-critical speech command is representative of a defined safety-critical action, operation or movement that is to be automatically executed by the medical apparatus based on the speech command. Therefore, the recognition of the second speech command in particular comprises the recognition of a speech command in the safety-critical safety class comprising first-failure safety speech commands.

The step of recognizing the second speech command can also be executed by applying the second computational linguistics algorithm. Herein, the step of recognizing the second speech command preferably follows the creation of a transcript (structured speech) of the speech signal or the creation of a semantic analysis result based on the transcript. Both can be comprised in the second speech analysis result.

Each safety-critical safety class can comprise a large number of different safety-critical speech commands. If the second computational linguistics algorithm does not recognize a safety-critical speech command, the first and second speech command are not compared and a verification signal is created that indicates that no second speech command is present. The method is aborted and the first speech command is discarded.

If the second computational linguistics algorithm recognizes a safety-critical speech command, the first and second speech command are compared. If the comparison does not identify any conformity of the two speech commands, a verification signal is generated that does not confirm the first speech command and this is likewise discarded. If the comparison identifies conformity of the two speech commands, a verification signal is generated that confirms the first speech command.

The comparison is used to ascertain a conformity measure between the two recognized speech commands. The conformity criterion is only satisfied if, for example, the first and second speech command are identified as identical. In other embodiments, a lower conformity measure can be sufficient to satisfy the predefined conformity criterion. Accordingly, according to one or more example embodiments of the present invention, in particular threshold values dependent upon the second speech command can be stored for the set of possible second speech commands, wherein the threshold values can represent a respective safety level.

The second trained function or the second trained machine learning algorithm also comprises a neural network, which can be substantially embodied as described with reference to the first trained function.

According to some embodiments of the invention, the second neural network is also a trained network. The training of the neural network is preferably performed in the sense of ‘supervised learning’ based on training data of a training data set, namely known pairs of input and output data, as described above. Therefore, according to one or more example embodiments of the present invention, in some embodiments, the second neural network, i.e., the second trained function of the second computational linguistics algorithm, is trained in a training phase to analyze the captured audio signal and to recognize therefrom a second speech command corresponding to one of the safety-critical safety classes, in particular the safety class comprising the first-failure safety speech commands. In some embodiments, the second speech command can correspond to the output data of the second trained function. In other embodiments, the second trained function also takes over the step of comparing the first and second speech command.

Safety-critical speech commands to be recognized by the second computational linguistics algorithm have a characteristic feature combination, i.e., a characteristic frequency pattern, amplitude, modulation, or the like, that in particular differs from the feature combination of the speech commands that are to be recognized by the first computational linguistics algorithm. Safety-critical speech commands, in particular first-failure safety speech commands, can, for example, be characterized by a minimum number of syllables, for example three or more. Or, they have unique phonetic features, i.e., phonetic features that can hardly be confused, so that a similarity to other speech commands or other speech input in general and the associated risk of confusion is minimized from the outset.

Accordingly, in the training phase, the second trained function also learns to assign one of the safety-critical speech commands based on a feature combination extracted from the audio signal in the sense of the second speech analysis result. The training phase can also comprise manual assignment of training input data in the form of speech input to individual speech commands.

As with the first trained function, a first group of neural network layers can also be directed at extracting or ascertaining the acoustic features of an audio signal and providing the second speech analysis result with the second trained function. Reference is made to the previous description, which is also applicable here. The second speech analysis result can also be used as an input data set for a second group of neural network layers, the ‘classifier’, which assigns one of the safety-critical speech commands to the second speech analysis result. The second trained function can advantageously be embodied to assign a failure output to the second speech command if no safety-critical speech command was recognized. If the second trained function does not recognize a safety-critical speech command, the first speech command is always discarded in the interest of human and device safety.

Here, once again, the individual functions can alternatively be executed by a plurality of, in particular two, independent neural networks.

The classification of the audio signal in one of the safety-critical speech commands, in particular first-failure safety speech commands, based on the second speech analysis result can also be based on a comparison of an extracted, second feature vector of the audio signal with a large number of feature vectors specific to and stored for each safety-critical speech command. For each safety-critical speech command, in particular first-failure safety speech command, in some embodiments of the invention, exactly one feature vector is stored in order to take account of safety requirements for safety-critical actions or movements of the medical apparatus. The comparison of the feature vectors can comprise an individual comparison of individual, preferably all, features comprised by a feature vector. Alternatively or additionally, the comparison can be based on a feature parameter derived from the respective feature vector, which takes account of a subset or all individual features. The conformity measure emerging from the comparison for the feature vectors or feature parameter indicates which safety-critical speech command is assigned or that no safety-critical speech command was recognized. The safety-critical speech command assigned as the second speech command is the one with the greatest similarity or a similarity to above a defined threshold value. Otherwise, reference is made to the statements relating to the first trained function.

Therefore, a key difference between the first and second trained function can in particular lie in the nature or scope of the training data. Whereas the first trained function is trained with a first training data set comprising a broad and diverse set of audio signals comprising human speech, which can comprise a wide number of different speech commands corresponding to a wide number of command classes and further general speech input that cannot be assigned to any command class, the second trained function is trained with a second training data set that is limited to specific concrete safety-critical speech commands, in particular first-failure safety speech commands, i.e., phonetically unique speech commands, that are difficult to confuse. In particular, in some embodiments, the second training data set is a subset of the first training data set, wherein, in some embodiments, the subset may only relate to first-failure safety speech commands. In this respect, according to one or more example embodiments of the present invention, the second trained function can be trained via a small training vocabulary and, in contrast, the first trained function can be trained with a large training vocabulary.

A further difference between the first and second trained function can be in the embodiment of the verification function or the classification function, which is preferably executed via the second group of neural network layers. Whereas the first trained function is embodied to classify a speech input into a large number of different speech commands corresponding to a wide variety of different categories, the second trained function is embodied to classify speech input into only a small set of safety-critical speech commands corresponding to a small number of categories.

In particular, according to one or more example embodiments of the present invention, the first trained function and the second trained function differ in the nature or type of neural network used in each case. In this way, it is, for example, possible to reduce the risk of occurrence of similar systematic failures in speech command recognition by the first trained function and the second trained function.

Particularly preferably, speech recognition algorithms that are known per se and available can be used with the first trained function. In some implementations of one or more example embodiments of the present invention, the second trained function corresponds to a speech recognition algorithm generated in the context of a secure, for example manufacturer's, software development process.

Whereas the first trained function can, for example, be embodied as a feedforward network, the second trained function can, for example, be embodied as a recurrent or feedback network in which nodes of a layer are also linked to themselves or to other nodes in the same and/or at least one previous layer.

According to some implementations, the first computational linguistics algorithm can be implemented as a so-called front-end algorithm hosted, for example, in a local computing unit of the medical apparatus or in a local speech recognition module. As a front-end, the processing can in particular take place effectively in real time so that the result can be obtained with virtually no significant time delay. Accordingly, the second computational linguistics algorithm can be implemented as a so-called back-end algorithm hosted, for example, in a remote computing facility, such as, for example, a real server-based computing system or a virtual cloud-computing system. In a back-end implementation, it is in particular possible to use complex analysis algorithms requiring high computing power. Accordingly, the method can comprise transmitting the audio signal to a remote computing facility and receiving one or more analysis results from the remote computing facility. In alternative implementations, the second computational linguistics algorithm can also be implemented as a front-end algorithm. Conversely, the first computational linguistics algorithm can also be implemented as a back-end algorithm.

According to a large number of preferred implementations of one or more example embodiments of the present invention, analyzing the audio signal comprises

-   -   tokenizing for segmenting letters, words and/or sentences within         the audio signal and the first and/or second speech command are         recognized based on first tokenization information and/or second         tokenization information, and/or     -   semantic analysis of the audio signal and the first and second         speech command are recognized based on first semantic         information and second semantic information.

Tokenization and/or semantic analysis can also be applied to user input directed at the confirmation of the first speech control command in the form of speech input via the further computational linguistics algorithm, as described in more detail below.

In computational linguistics, tokenization refers to the segmentation of text into units at letter, word and sentence level. According to some implementations, tokenization can comprise converting speech contained in the audio signal into text. In other words, a transcript can be created and then tokenized. For this purpose, it is possible to use a plurality of methods that are known per se, based, for example, on the use of format analysis, hidden Markov models, neural networks, electronic dictionaries and/or language models. This analysis step is preferably executed via the first, second and/or the further trained function, as described in the introduction.

The first and/or second speech analysis result can comprise first or second tokenization information. The use of tokenization information enables account to be taken of the structure of speech input for ascertaining a speech command or a user intention in general.

According to some implementations, a step for analyzing the audio signal according to one or more example embodiments of the present invention comprises semantic analysis of the audio signal to ascertain an operator speech command. Accordingly, the first and/or second speech analysis result can comprise corresponding semantic information.

In other words, the aim of semantic analysis is to infer the meaning of the operator speech input. In particular, semantic analysis can comprise an upstream speech recognition step (speech to text) and/or a tokenization step.

According to some implementations, the semantic information indicates whether or not the audio signal contains one or more user intentions. Herein, the user intention can in particular be operator speech input directed at one or more relevant speech commands. Herein, the speech commands can in particular be speech commands relevant for controlling the medical apparatus. According to some implementations, the semantic information indicates or contains at least one property of a user intention contained in the audio signal. Therefore, the semantic analysis is used to extract certain acoustic characteristics or properties from the speech input that can be taken into account or be relevant for the determination of a speech command.

According to a further aspect, one or more example embodiments of the present invention provides a speech control apparatus for speech control of a medical apparatus. The speech control apparatus comprises at least one interface for capturing an audio signal containing operator speech input directed at controlling the apparatus. The speech control apparatus furthermore comprises at least one evaluation unit embodied to analyze the audio signal and to provide a first speech analysis result, to recognize a first speech command based on the first speech analysis result, to assign the first speech command to a safety class, wherein a safety class is provided for safety-critical speech commands, to ascertain a verification signal for the first speech command and, possibly, provide it for further processing. The speech control apparatus further comprises a control unit embodied to generate a control signal for controlling the medical apparatus based on the first speech command and the verification signal provided that the first speech command has been confirmed based on the verification information, wherein the control signal is suitable for controlling the medical apparatus according to the first speech command. The speech control apparatus also comprises an interface for inputting the control signal into the medical apparatus.

For the purposes of one or more example embodiments of the present invention, a medical apparatus is in particular a physical medical apparatus. The medical apparatus is typically used to treat and/or examine a patient. The medical apparatus can in particular be embodied to perform and/or support a medical procedure. The medical procedure can comprise an imaging and/or interventional and/or therapeutic procedure, but also monitoring of a patient. In particular, the medical apparatus can comprise an imaging modality, such as, for example, a magnetic resonance device, a single-photon emission computed tomography device (SPECT device), a positron emission tomography device (PET device), a computed tomography device, an ultrasound device, an X-ray device or an X-ray device embodied as a C-arm device. The imaging modality can also be a combined medical imaging device comprising any combination of several of the aforementioned imaging modalities. Furthermore, the medical apparatus can include an interventional and/or therapy apparatus, such as, for example, a biopsy apparatus, a radiation-emitting or radiotherapy apparatus for irradiating a patient, and/or an interventional apparatus for performing an intervention, in particular a minimally invasive intervention. According to further implementations, the medical apparatus can additionally or alternatively comprise patient monitoring modules, such as, for example, an ECG device, and/or a patient care device, such as, for example, a ventilator, an infusion device and/or a dialysis device. Herein, the treatment and/or examination and/or monitoring of the patient via the medical apparatus is typically supported by an operator, for example nursing staff, technical staff, X-ray assistants or physicians.

The at least one evaluation unit and the control unit can be embodied as one or more central and/or decentralized computing units. The computing unit(s) can in each case have one or more processors. A processor can be embodied as a central processing unit (CPU/GPU). In particular, the at least one evaluation unit and the control unit can in each case be implemented as a part or module of a medical apparatus to be controlled by speech input. In some implementations, the at least one evaluation unit can be embodied as a submodule of the control unit or vice versa. Alternatively, the at least one evaluation unit can be implemented as a local or cloud-based processing server. Furthermore, the at least one evaluation unit can comprise one or more virtual machines.

In preferred implementations, the speech control apparatus comprises two separate evaluation units, in each case as described above and preferably implemented on separate hardware or in different software modules. Herein, a first evaluation unit is embodied to execute the following steps according to one or more example embodiments of the present invention: analyze the audio signal and provide a first speech analysis result, recognize a first speech command based on the first speech analysis result and assign the first speech command to a safety class. The second evaluation unit is embodied to ascertain verification information for the first speech command, provided that it has been assigned to a safety class for safety-critical speech commands, and to provide a verification signal based on the verification information.

In this way, the present invention is embodied to feature the conventional control-protect (CP) structure of a first-failure safety control system for control commands in the form of speech input, in which the first evaluation unit forms part of the control path (C-path) and the second evaluation unit forms the test path (P-path).

The interface of the speech control apparatus can be generally embodied for data exchange between the speech control apparatus and further components and/or for data exchange between components or modules of the speech control apparatus. Insofar, the interface can be implemented in the form of one or more individual data interfaces, which may have a hardware and/or software interface, for example a PCI bus, a USB interface, a FireWire interface, a ZigBee interface or a Bluetooth interface. The interface can furthermore have an interface of a communication network, wherein the communication network can have a local area network (LAN), for example an intranet or a wide area network (WAN). Accordingly, the one or more data interfaces can have a LAN interface or a wireless LAN interface (WLAN or WIFI). The interface can furthermore be embodied to communicate with the operator via a user interface. Accordingly, the interface can be embodied to display speech commands via the user interface and to receive related user input via the user interface. In particular, the interface can comprise an acoustic input apparatus for registering the audio signal and, in some embodiments, an acoustic output apparatus for outputting an audio signal comprising a prompt to confirm the first speech command.

The advantages of the proposed apparatus substantially correspond to the advantages of the proposed method. Features, advantages or alternative embodiments/aspects can likewise be applied to the other claimed subject matter and vice versa.

According to a further aspect, one or more example embodiments of the present invention provides a medical system comprising the speech control apparatus according to one or more example embodiments of the present invention and a medical apparatus for performing a medical procedure.

In a further aspect, one or more example embodiments of the present invention relates to a computer program product, which comprises a program and can be loaded directly into a memory of a programmable computing unit, and program means, for example libraries and auxiliary functions, in order to execute a method for speech control of a medical apparatus in particular according to the aforementioned implementations/aspects when the computer program product is executed.

Furthermore, in a further aspect, one or more example embodiments of the present invention relates to a computer-readable storage medium on which readable and executable program sections are stored in order to execute all the steps of a method for speech control of a medical apparatus according to the aforementioned implementations/aspects when the program sections are executed by a computing unit.

Herein, the computer program product can comprise software with a source code, which still has to be compiled and linked or only has to be interpreted or an executable software code that only needs to be loaded into the computing unit for execution. The computer program product enables the methods according to one or more example embodiments of the present invention to be executed quickly, identically repeatedly and robustly. The computer program product is configured such that it can execute the method steps according to one or more example embodiments of the present invention via the computing unit. Herein, the computing unit must in each case fulfill the requisite conditions such as, for example, having a corresponding random-access memory, a corresponding processor, or a corresponding logic unit so that the respective method steps can be executed efficiently

The computer program product is, for example, stored on a computer-readable storage medium or held on a network or server from where it can be loaded into the processor of the respective computing unit, which can be directly connected to the computing unit or embodied as part of the computing unit. Furthermore, control information of the computer program product can be stored on a computer-readable storage medium. The control information of the computer-readable storage medium can be embodied such that it carries out a method according to one or more example embodiments of the present invention when the data carrier is used in a computing unit. Examples of computer-readable storage media are DVDs, magnetic tapes or USB sticks on which electronically readable control information, in particular software, is stored. When this control information is read from the data carrier and stored in a computing unit, all the embodiments/aspects according to one or more example embodiments of the present invention of the above-described methods can be performed. Thus, one or more example embodiments of the present invention can also be based on said computer-readable medium and/or said computer-readable storage medium. The advantages of the proposed computer program products or the associated computer-readable media substantially correspond to the advantages of the proposed methods.

FIG. 1 is a schematic functional block representation of a system 100 for controlling a medical apparatus 1. The system 100 comprises the medical apparatus 1 which is embodied to perform a medical procedure on a patient. The medical procedure can comprise an imaging and/or interventional and/or therapeutic procedure. The system furthermore comprises a speech control apparatus 10.

The medical apparatus 1 can comprise an imaging modality. The imaging modality can generally be embodied to image an anatomical region of a patient when the patient is brought into an acquisition region of the imaging modality. The imaging modality is, for example, a magnetic resonance device, a single-photon emission computed tomography device (SPECT device), a positron emission tomography device (PET device), a computed tomography device, an ultrasound device, an X-ray device or an X-ray device embodied as a C-arm device. The imaging modality can also be a combined medical imaging device comprising any combination of several of the imaging modalities named.

Furthermore, the medical apparatus 1 can have an interventional and/or therapeutic apparatus. The interventional and/or therapeutic apparatus can generally be embodied to perform an interventional and/or therapeutic medical procedure on the patient. For example, the interventional and/or therapeutic apparatus can be a biopsy apparatus for taking a tissue sample, a radiation-emitting or radiotherapy apparatus for irradiating a patient, and/or an interventional apparatus for performing an intervention, in particular a minimally invasive intervention. According to some embodiments of the invention, the interventional and/or therapeutic apparatus can be automated or at least partially automated and in particular robot-controlled. The radiation-emitting or radiotherapy apparatus can, for example, include a medical linear accelerator or another radiation source. For example, the interventional apparatus can have a catheter robot, a minimally invasive surgical robot, an endoscopy robot, etc.

According to further embodiments, the medical apparatus 1 can additionally or alternatively have units and/or modules that support the performance of a medical procedure, such as, for example, a patient support apparatus that can be controlled in an at least partially automated manner, and/or monitoring devices for monitoring the patient's condition, such as, for example, an ECG device, and/or a patient care device, such as, for example, a ventilator, an infusion device and/or a dialysis device.

According to some embodiments of the invention, one or more components of the medical apparatus 1 should be controllable by one or more operator speech input types. For this purpose, the system 100 has a speech control apparatus 10 comprising an interface with an acoustic input apparatus 2.

The acoustic input apparatus 2 is used to record or capture an audio signal E1, i.e., to record spoken sounds generated by an operator of the system 100. The input apparatus 2 can, for example, be implemented as a microphone. The input apparatus 2 can, for example, be arranged in a stationary manner on the medical apparatus 1 or elsewhere, such as in a remote control room. Alternatively, the input apparatus 2 can also be embodied as portable, for example as a microphone of a headset that can be carried by the operator. In this case, the input apparatus 2 advantageously includes a transmitter 21 for wireless data transmission.

The speech analysis apparatus 10 has an input 31 for receiving signals and an output 32 for providing signals. The input 31 and the output 32 can form an interface facility of the speech analysis apparatus 10. The speech analysis apparatus 10 is generally configured to perform data processing operations and to generate electrical signals.

For this purpose, the speech control apparatus 10 can have at least one computing unit 3. The computing unit 3 can, for example, comprise a processor, for example in the form of a CPU or the like. The computing unit 3 can be embodied as at least one central evaluation unit, for example embodied as an evaluation unit with one or more processors. The computing unit 3 can preferably comprise a control unit embodied to generate control signals for the medical apparatus.

The computing unit 3 can in particular be at least partially embodied as a control computer (also called system control) of the medical apparatus 1 or as part of the same. According to one or more example embodiments of the present invention, the computing unit 3 comprises units or modules embodied to execute a, in particular standardized, safety function (also called SIL, safety integrity level) units). The standardized safety function is used to minimize an operating risk of the medical apparatus 1 due to the execution of an incorrectly recognized control command. In particular, the safety function enables the safeguarding of a first failure in the machine recognition of a control command from speech input. According to further implementations, functionalities and components of the computing unit 3 can be distributed in a decentralized manner across a plurality of computing units or control modules of the system 100.

Furthermore, the speech control apparatus 10 has a data memory 4, and in particular a non-volatile data memory that can be read by the computing unit 3, such as a hard disk, a CD-ROM, DVD, Blu-ray disk, floppy disk, flash memory or the like. The data memory 4 can generally store software P1, P2, Pn configured to prompt the computing unit 3 to perform the steps of a method.

As depicted schematically in FIG. 1 , the input 31 of the speech control apparatus 10 is connected to the input apparatus 2. The input can likewise be connected to the medical apparatus 1. The input 31 can be configured for wireless or wired data communication. For example, the input 31 can have a bus port. Alternatively or additionally to a wired port, the input 31 can also have an interface, for example a receiver 34 for wireless data transmission. For example, as depicted in FIG. 1 , the receiver 34 can be in data communication with the transmitter 21 of the input apparatus 2. The receiver 34 provided can, for example, be a WIFI interface, a Bluetooth interface or the like.

The output 32 of the speech control apparatus 10 is, on the one hand, connected to the medical apparatus 1. The output 32 can be configured for wireless or wired data communication. For example, the output 32 can have a bus port. Alternatively or additionally to a wired port, the output 32 can also have an interface for wireless data transmission, for example to an online module OM1, for example a WIFI interface, a Bluetooth interface or the like.

In some embodiments, the output 32 can be embodied to output an audio signal AI, i.e., acoustic output of spoken natural speech generated by an output apparatus 35. The output apparatus 35 can in particular be embodied to generate speech output by machine based on a signal comprising structured text. The output apparatus 35 can, for example, be implemented as a loudspeaker. The output apparatus 35 can likewise be arranged in a stationary manner on the medical apparatus 1 or in a remote control room. Alternatively, the output apparatus 35 can also be implemented as portable, in particular, it can be embodied as combined with the input apparatus 2, for example as an aforementioned headset.

The speech control apparatus 10 is configured to generate one or more control signals C1 for controlling the medical apparatus 1 and provide them at the output 32. The control command C1 prompts the medical apparatus 1 to perform a certain work step or a sequence of steps. For example, using the example of an imaging modality embodied as an MR device, such steps can, for example, relate to the performance of a certain scan sequence with a certain excitation of magnetic field by a generator circuit of the MR device. Furthermore, such steps can relate to the movement of movable system components of the medical apparatus 1, such as, for example, the movement of a patient support apparatus or the movement of emission or detector components of an imaging modality. The steps can in particular also relate to the release or start of X-radiation.

To provide the control signal C1, the computing unit 3 can have different modules M1-M3. A first module M1 corresponding to a first evaluation unit is embodied to analyze the audio signal E1 and, on the basis thereof, to provide a first speech analysis result, to recognize a first speech command SSB1 based on the first speech analysis result and to assign the first speech command SSB1 to a safety class SK. For this purpose, the module M1 can be embodied to apply a first computational linguistics algorithm P1 to the audio signal E1. In particular, the module M1 is embodied, to execute method steps S20 to S40.

The first speech command SSB1 can then be input into a further module M2 corresponding to a second evaluation unit, independent of the first evaluation unit, if it has been assigned to a safety class SK comprising safety-critical speech commands. Module M2 is embodied to ascertain a verification signal VS to confirm the first speech command SSB1, in particular according to at least one execution of method step S50. For this purpose, the module M2 can be embodied to apply a second or at least one further computational linguistics algorithm P2, Pn to the audio signal E1 or a further audio signal E2, which is likewise input via the input apparatus 2 and can correspond to user input for confirming the first speech command SSB1. Herein, the second computational linguistics algorithm P2 can be embodied to recognize a second speech command SSB2 in the audio signal E1. The further computational linguistics algorithm Pn can also be embodied to recognize at least one confirmatory keyword in at least one second audio signal E2. For this purpose, the second module M2 can also be embodied to previously generate speech output A1 based on the first speech command SSB1 to prompt the operator to confirm the first speech command SSB1 (again using a further computational linguistics algorithm), wherein the prompt is output acoustically via the output apparatus 35 of the output 32.

The second module M2 is in particular embodied to generate a verification signal VS comprising verification information confirming the first speech command SSB1 based on a comparison between the first and second speech command SSB1, SSB2 or based on the recognition of a predefined keyword in the at least one second audio signal E2. The verification signal VS can preferably also comprise the first speech command SSB1.

The verification signal VS is given to a third module M3 corresponding to a control unit of the speech control apparatus 10. Module M3 is embodied to provide, based on the first speech command SSB1 or the verification signal VS, one or more control signals C1 suitable for controlling, the medical apparatus 1 according to the first speech command SSB1.

If the first speech command SSB1 belongs to a safety class SK relating to non-safety-critical speech commands, the module M2 is not activated. Module M1 then enters the recognized first speech command SSB1 directly into the module M3, for example. Here, verification according to one or more example embodiments of the present invention can be omitted.

Herein, subdivision into modules M1-M3 is only intended to simplify the explanation of the mode of operation of the computing unit 3 and should not be understood to be restrictive. Herein, the modules M1-M3 can in particular also be understood to be computer program products or computer program segments, which, when executed in the computing unit 3, implement one or more of the functions or method steps described below.

Preferably, at least module M2 is embodied as an SIL unit for executing a safety function. According to one or more example embodiments of the present invention, the safety function is directed at checking or confirming the first recognized speech command SSB1 in at least one independent verification loop.

According to a conventional CP structure, module M1 and module M3 together form part of the C-path, while module M2 forms part of the P-path.

FIG. 2 is a schematic functional block representation of a system 100 for performing a medical procedure on a patient according to a further embodiment.

The embodiment shown in FIG. 2 differs from the embodiment shown in FIG. 1 in that the functionalities of the module M1 are at least partially outsourced to an online module OM1. Otherwise, the same reference symbols refer to the same components or components with the same function.

The online module OM1 can be stored on a server 61 with which the speech analysis apparatus 10 can enter into data exchange via an Internet connection and an interface 62 of the server 61. Accordingly, the speech control apparatus 10 can be embodied to transmit the audio signal E1 to the online module OM1. The online module OM1 can be embodied, based on the audio signal E1, to ascertain a first speech command SSB1 and, possibly, the associated safety class based on the audio signal E1 and return them to the speech control apparatus 10. Accordingly, the online speech recognition module OM1 can be embodied to make the first computational linguistics algorithm P1 available in a suitable online memory. Herein, the online module OM1 can be understood to be a centralized facility that provides speech recognition services for a plurality of clients, in particular local clients (in this context, the speech control apparatus 10 can be understood as a local client). The use of a central online module OM1 can be advantageous in that more powerful algorithms can be applied and more computing power can be expended.

In alternative implementations, the online speech recognition module OM1 can also “only” return the first speech analysis result. The first speech analysis result can then, for example, contain machine-usable text into which the audio signal E1 has been converted. Based on this, the module M1 of the computing unit 3 can identify the first speech command SSB1. Such an embodiment can be advantageous if the speech commands SSB1 depend on the circumstances of the medical apparatus 1 which the online module OM1 is unable to access and/or which the online module OM1 has not been prepared to take into account. The capacity of the online module OM1 is then used to create a first speech analysis result, but otherwise the speech commands are determined within the computing unit 3.

However, conversely, according to a further variation, not shown, further functions of the speech analysis apparatus 10 can be executed in a central server. For example, it is conceivable for the second computational linguistics algorithm P2 also to be hosted in an online module.

In the system 100 shown by way of example in FIG. 1 , the medical apparatus 1 is controlled by a method depicted as a flow diagram in FIG. 3 by way of example. The order of the method steps is not restricted either by the sequence depicted or by the numbering selected. For example, it is possible for the order of the steps to be interchanged. In some embodiments, individual steps can be performed in parallel. Once again, individual steps can be omitted.

Generally, herein, it is provided that the operator operating the medical apparatus 1 voices or speaks a command, for example by saying a sentence such as “Start scan sequence X” or “Bring the patient to the starting position”, the input apparatus 2 captures and processes an associated audio signal E1 and the speech control apparatus 10 analyzes the captured audio signal E1 and generates a corresponding control command C1 for actuating the medical apparatus 1. One advantage of this approach is that the operator can also perform other tasks while speaking, for example the preparation of the patient. This advantageously speeds up the workflow. Furthermore, this enables the medical apparatus 1 to be at least partially controlled in a “contactless” manner thus improving hygiene at the medical apparatus 1.

The method for speech control of the medical apparatus 1 comprises steps S10 to S70. The steps are preferably executed with the speech control apparatus 10. In step S10, an audio signal E1 containing operator speech directed at controlling the apparatus 1 is captured via the input apparatus 2. The audio signal E1 is provided to the speech control apparatus 10 via the input 31. A step S20 comprises analyzing the audio signal E1 to provide a first speech analysis result SAE1. Therefore, step S20 comprises the provision of a speech utterance relevant for controlling the medical apparatus as a first speech analysis result SAE1 from the audio signal E1. The generation of the speech analysis result can comprise a plurality of substeps.

One substep can be directed at first converting the sound information contained in the audio signal E1 into text information, i.e., generating a transcript. One substep can be directed at tokenizing the audio signal E1 or the operator speech input or the transcript T. Herein, tokenization refers to segmentation of the speech input, i.e., the spoken text into units at word or sentence level. Accordingly, the first speech analysis result SAE1 can comprise first tokenization information that indicates, for example, whether or not the operator has finished speaking a current sentence.

One substep can be directed at additionally or alternatively executing semantic analysis of the audio signal E1 or the operator speech input or the transcript T. Accordingly, the first speech analysis result SAE1 can comprise first semantic information about the operator speech input. Herein, the semantic analysis is directed at assigning a meaning to the speech input. For this purpose, for example, a word-by-word-wise or word-group-by word-group-wise comparison can be made with a general word and/or speech command database 5 or one that is specific to the medical apparatus 1 or a word library and/or speech command library 50 of the medical apparatus 1 or the system 100 according to one or more example embodiments of the present invention. In particular, in this step, for example, one or more statements contained in a command library 50 of the medical apparatus 1 can be assigned to the transcript T according to different speech commands. Thus, it is possible to recognize a user intention directed at a speech command.

The substeps described can be executed by a speech understanding module comprised by module M1; in particular these substeps can be executed by the online module OM1.

In step S30, a first speech command SSB1 is recognized based on the first speech analysis result SAE1. Here, in particular the semantic information representing a user intention is used in order to assign a corresponding speech command as a first speech command SSB1. In other words, the recognized speech command is assigned to one of numerous possible command classes, wherein different modes of expression, words, word sequences or word combinations representing the user intention corresponding to the speech command can be stored for a command class. Step S30 can also comprise a comparison of the first speech analysis result SAE1 with a command database 5 or command library 50.

In step S40, the first speech command SSB1 is assigned to a safety class SK. Here, at least one safety class for safety-critical speech commands is provided to which the first speech command SSB1 belongs. Herein, each speech command can be assigned to a safety class SK via a conventional lookup table or another assignment rule. According to one or more example embodiments of the present invention, now at least one of the possible safety classes is provided for safety-critical speech commands the execution of which by the medical apparatus 1 must satisfy specific standardized safety requirements. In particular, this comprises speech commands the execution of which must be implemented in a first-failure safe manner.

Steps S20 to S40 can, for example, be implemented by software P1 stored on the data memory 4 and which prompts the computing unit 3, in particular module M1 or online module OM1, to perform these steps. The software P1 can comprise a first computational linguistics algorithm comprising a first trained function which is applied to the audio signal, in particular for analyzing the audio signal E1. In this way, one or more example embodiments of the present invention implements a conventional CP architecture C-path.

If the first speech command SSB1 is a safety-critical speech command, in particular step S50 is executed in full.

In step S50, a verification signal VS for confirming the first speech command SSB1 is ascertained. According to one or more example embodiments of the present invention, the verification signal VS can be ascertained in different ways, as will be explained with reference to the further figures. According to one or more example embodiments of the present invention, the verification signal is ascertained with the independent module M2 of the computing unit 3. In this way, one or more example embodiments of the present invention implements an independent P-path to safeguard safety-critical speech commands, wherein, according to one or more example embodiments of the present invention, the safety function is based on a speech command obtained via machine speech processing methods.

In step S60, a control signal C1 for controlling the medical apparatus is generated based on the first speech command SSB1 and the verification signal VS provided that the first speech command SSB1 has been confirmed in step S50, wherein the control signal C1 is suitable for controlling the medical apparatus 1 according to the first speech command SSB1. In other words, the first speech command SSB1 is transferred in the form of an input variable or as part of the verification signal to the module M3 of computing unit 3 (or corresponding software stored, for example, on the data memory 4) and at least one control signal C1 is derived therefrom. In a step S70, the control signal C1 is input or transferred into the medical apparatus 1 via the output 32.

FIG. 4 is a flow diagram for ascertaining a verification signal VS for the first speech command SSB1 in one embodiment of the invention in which the confirmation of the first speech command SSB1 requires user interaction. The user interaction again preferably takes place in the form of speech so that this embodiment also ensures simple and quick operation of the medical apparatus 1 and a high standard of hygiene.

The steps depicted in FIG. 4 , the order of which is likewise not mandatorily determined by the sequence, take place in the framework of step S50 in FIG. 3 . Accordingly, ascertaining the verification signal VS comprises a step S51-1 in which the first speech command SSB1 and a prompt A1 to confirm the first speech command SSB1 are output to the operator. In a preferred embodiment, the prompt A1 and the first speech command SSB1 are output in the form of an audio signal. In other embodiments, however, the output may also take place differently, for example via an optical output interface in the form of a display. The prompt A1 can comprise information that the first speech command SSB1 has been recognized and about which user input (content criterion IK) is specifically required for the confirmation thereof and/or within which time period (time criterion) the confirmation must take place. For example, the prompt can be: ‘Command XY recognized, please confirm with ‘YES’ within 5 seconds’. The module M2 is embodied, for example, to provide a structured speech data stream based on the first speech command SSB1, and, based thereon, sound information that is generated there and supplied to the output apparatus 35 of the output 32 for conversion into a sound signal. For this purpose, software Pn can be stored in the memory 4 in a manner retrievable by module M2. The software Pn can comprise a further computational linguistics algorithm Pn for machine generation of natural speech. Here, the further computational linguistics algorithm Pn can be embodied as an algorithm for natural speech generation (or natural language generation, NLG). Alternatively, for a large number of command classes, in each case a predefined structured speech data stream or a sound signal can be stored in a corresponding output database in a retrievable manner; this is recognized by the module M2 according to the first speech command SSB1 and transferred to the output to generate the audio signal AI.

In an optional step S51-11, the prompt for user input A1 can be supplemented by an optional request A2 for speech control information SSI specific to the first speech command SSB1, which, like the audio signal AI, is output to the operator. Herein, speech control information SSI is information necessary for the execution of the first speech command SSB1, which can comprise the specific necessary parameters or indications, for example a length indication according to a desired adjustment path. The optional request A2 can, for example, be: ‘How far (in cm) should the bench be moved upward?’.

In step S51-2, user input E2 of the operator directed at the confirmation of the first speech command is now captured, here in the form of an audio signal E2. The capturing can, as already described above with reference to audio signal E1, take place via the input 31 of the speech control apparatus 10 and the input apparatus 2 and comprise corresponding preprocessing steps (digitization, storage, etc.). Optionally, the input 31 and the input apparatus can also capture user input comprising the requested speech control information SSI and supply it to the module M2 for further processing. Accordingly, herein, the audio signal E2 can also comprise the speech control information SSI.

Step S51-3 is directed at evaluating the audio signal E2 by module M2 in order to infer the content of the audio signal. For this purpose, software, which can likewise be stored in a retrievable manner in the memory 4, can in particular be provided in the form of a further computational linguistics algorithm Pn. In some embodiments, this further computational linguistics algorithm Pn can be embodied to recognize keywords, in particular short keywords, directed at command confirmation such as ‘Yes’, ‘Yes, please.’ ‘Confirmed’, ‘Check’ or the like.

In addition, the further computational linguistics algorithm Pn can also be embodied to derive speech control information SSI from the audio signal E2. For each command class or for each speech command, individually defined keywords that the further computational linguistics algorithm Pn has to recognize in the audio signal can be defined and stored.

Here, once again, a substep can be directed at tokenization of the second audio signal E2 and provision of the tokenization information. Here, once again, a further substep can be directed at semantic analysis of the second audio signal E2 and the provision of semantic information, as described with reference to the first computational linguistics algorithm.

Therefore, in step S51-3, module M2 checks whether words or word sequences comprised in the audio signal correspond to a keyword stored for the first speech command SSB1. In this way, module M2 checks whether or not a predefined content criterion IK of the user input E2 directed at the confirmation is satisfied. The content criterion IK is only satisfied if the stored keyword is recognized.

Alternatively or additionally, module M2 also checks whether the user input satisfies a time criterion ZK. For this purpose, a temporal threshold value specific to and stored for the first speech command SSB1 can be monitored according to a maximum time period or duration in which the audio signal E2 must be captured after the prompt A1 has been output. The time criterion ZK is only satisfied if the input is made quickly enough.

If the content criterion IK and/or the time criterion ZK is satisfied, the first speech command SSB1 is verified or confirmed.

In some embodiments of the invention, in particular steps S51-1 to S51-3 can be run through multiple times, for example two or three times. These multiple verification loops can in particular be provided for safety-critical speech commands with a high safety level, in particular the safety class comprising first-failure safety speech commands.

In step S51-4, module M2 of the speech control apparatus 10 further generates a verification signal VS based on the test result from step S51-3. Herein, the test result can take account of the results all the test loops run through or only the result of the last test loop past through. The verification signal VS is then transmitted to module M3 corresponding to a control unit of the speech control apparatus, which (step S60, FIG. 3 ) generates the control signal C1 according to the first speech command SSB1 confirmed via the verification signal VS.

In this embodiment of the invention, safety requirements for the execution of a safety-critical speech command are met by starting, based on the first recognized speech command SSB1, a safety function in the form of the verification loop(s) executed by module M2 in which the verification is implemented via manual confirmation by user input, i.e., conventionally. Monitoring the content criterion IK and the time criterion ZK enables the implemented safety function to be verified in a conventional manner and makes it resilient in terms of safety, although the output signal for the verification loop (the first speech command SSB1) originates from an analysis that is not resilient in terms of safety. Therefore, if module M1 makes an error when identifying the first speech command SSB1, this error is corrected by module M2 and the first speech command SSB1 is not executed.

The variability of the input space, i.e., the possibility of limiting or extending the permissible commands for the first or the further computational linguistics algorithm, which are applied to the audio signals E1, E2, also facilitates the verification of the system according to one or more example embodiments of the present invention and enables simplification of the error models to be assumed. The system according to one or more example embodiments of the present invention is furthermore used in an environment that is known per se and therefore possible disruptive influences such as, for example, background noise are also known to a large extent. This facilitates the creation of a robustness test for the system according to one or more example embodiments of the present invention and the generation of critical expected input scenarios.

In a further optional step S51-5, the initial specified time criterion ZK can be adjusted in dependence on the first speech command SSB1. In particular, step S51-1 can be performed at a different time than the other steps S51-1 to S51-4. In some embodiments, the adjustment of the time criterion ZK comprises adding or subtracting a time difference AZK to/from the previous time period defined as a threshold value. The adjustability of the time criterion ZK primarily enables the method according to one or more example embodiments of the present invention to be scaled toward greater ease of operation (AZK is added) or a higher command reliability (AZK is subtracted).

In further embodiments (not depicted), in the sense of flexible scalability of the method, furthermore a step can be provided for alternatively or additionally adjusting the content criterion IK, so that for example more or fewer keywords can be recognized as belonging to a speech command.

The number of verification loops that have to be run through before the verification signal is created can also be changed in the sense of scalability.

FIG. 5 is a further flow diagram for ascertaining a verification signal VS for the first speech command SSB1 in a further embodiment of the invention in which the first speech command SSB1 can be confirmed without user interaction. In other words, in this embodiment, the invention enables particularly simple and fast operation of the medical apparatus 1 with only initial speech input in the sense of the audio signal E1.

The steps depicted in FIG. 5 the order of which is likewise not mandatorily specified by the sequence take place in the same way as in the framework of step S50 in FIG. 3 . Accordingly, step S50, i.e., ascertaining the verification signal VS, comprises the following steps.

Step S52-1 is directed at an analysis of the audio signal E1 for providing a second speech analysis result SAE2 and step S52-2 is directed at recognizing a second speech command SSB2 based on the second speech analysis result SAE2.

Steps S52-1 and S52-2 are implemented by software P2 stored on the data memory 4 and which prompt the computing unit 3, in particular module M2, to perform these steps. The software P2 can comprise a second computational linguistics algorithm P2 comprising a second trained function, which like the software P1 is applied to the audio signal E1, in particular for analyzing the audio signal E1.

Step S52-1 can likewise comprise tokenization of the audio signal E1 and/or semantic analysis of the audio signal E1.

The second computational linguistics algorithm P2 can advantageously comprise a second trained function. It is characteristic of the present invention that the first trained function and the second trained function are different from one another. In particular, the second trained function is embodied only to identify safety-critical speech commands, in particular speech commands that are to feature first-failure safety, in the audio signal E1, whereas the first trained function is embodied to recognize a very broad vocabulary relating to a wide variety of operator speech input and in particular also non-safety-critical speech commands. In this sense, the second trained function is embodied as specific to safety-critical speech commands. Therefore, the second trained function does not recognize non-safety-critical speech commands or general speech input. In this respect, at least step S52-2 is specific to recognizing a safety-critical speech command as the second speech command SSB2.

Safety-critical speech commands are characterized by a characteristic feature combination, consisting, for example, of the frequency pattern, amplitude, modulation, or the like. In addition, safety-critical speech commands, in particular first-failure safety speech commands, in particular have a minimum number of syllables of three or more. The greater the number of syllables in a speech command, the easier it is to distinguish from other speech commands. This minimizes the risk of confusion with other speech commands.

The specificity of steps S52-1 and S52-2 is achieved in that the second trained function is embodied differently from the first trained function. A key difference between the first and second trained function can be between the training data used in each case. The first training data set for the first trained function comprises a broad and diverse vocabulary with respect to a wide variety of speech commands or general speech input. On the other hand, the second training data set for the second trained function is limited to a vocabulary directed at specific speech commands, in particular phonetically unique speech commands, in order to be able to recognize safety-critical speech commands, in particular first-failure safety speech commands, unambiguously with a low failure rate. In this respect, according to one or more example embodiments of the present invention, the second trained function can be trained via a small training vocabulary and, in contrast, the first trained function can be trained with a large training vocabulary. According to one or more example embodiments of the present invention, the trained functions themselves can differ, especially in the embodiment of the verification function or the classification function. The first trained function has a large number categories corresponding to a large number of different speech commands. On the other hand, the second trained function is limited to a lower number of categories corresponding to a small number of safety-critical speech commands, in particular specific to the medical apparatus. By using different types of trained functions, one or more example embodiments of the present invention reduces the risk of occurrence of similar systematic failures in speech command recognition by the first trained function and the second trained function.

Therefore, if, in step S52-2, the second trained function identifies a speech command as a second speech command SSB2 from the second speech analysis result SAE2, this is per se a safety-critical speech command.

In this embodiment, due to the different embodiment of the first and second trained functions, the risk of executing a first speech command SSB1 incorrectly recognized in the module M1 is minimized since systematic speech command recognition failures of the first trained function are very unlikely to be repeated by the second trained function.

In a step S52-3, the conformity between the first and second speech command SSB1, SSB2 is now checked with reference to a conformity criterion UK. Herein, a conformity measure between the two speech commands is compared with a predefined threshold value specific to the first and/or second speech command SSB1/SSB2. The threshold value or the required similarity measure can vary from speech command to speech command. According to one or more example embodiments of the present invention, threshold values of speech commands of a high safety level, i.e., in particular speech commands that are to feature first-failure safety, are embodied larger than speech commands of a lower safety level.

If test step S52-3 reveals that first and the second speech command SSB1, SSB2 have a conformity measure at or above the threshold value, the first speech command SSB1 is confirmed.

In step S52-4, module M2 of the speech control apparatus 10 further generates a verification signal VS based on the test result from step S53-3. The verification signal VS is then transmitted to module M3 corresponding to the control unit of the speech control apparatus 10, which (in step S60 in FIG. 3 ) generates the control signal C1 according to the first speech command SSB1 confirmed via the verification signal VS.

Optionally, method steps S51-1 to S51-3 can be added to the method depicted in FIG. 5 after the second safety-critical speech command SSB2 has been recognized in step S52-2, wherein the test result of step S51-3 is likewise included in the generation of the verification signal in step S52-4. In other words, in this embodiment the verification signal VS also depends on the test result of step S51-3 ab.

FIG. 6 shows an artificial neural network 400 such as can be used in methods according to FIGS. 3 to 5 . In particular, the neural network 400 shown can be the first or second trained function of the first or the second computational linguistics algorithm P1, P2. The neural network 400 responds to input values to a large number of input nodes xi 410 that are applied in order to generate one or a large number of outputs oj. In this exemplary embodiment, the neural network 400 learns by adjusting the weighting factors wi (weights) of the individual nodes based on training data. Possible input values of the input nodes xi 410 can, for example, be speech input or audio signals of a first or second training data set. The neural network 400 weights 420 the input values 410 based on the learning process. In some embodiments, the output values 440 of the neural network 400 correspond to a first or a second speech command SSB1, SSB2. In other embodiments, the output values 440 of the neural network can also comprise an indication of a safety class SK of the first speech command SSB1 or a result of a check of a conformity criterion between the first and second speech command SSB1, SSB2. The output 440 can take place via a single output node or a large number of output nodes oj.

The artificial neural network 400 preferably comprises a hidden layer 430 comprising a large number of nodes hj. A plurality of hidden layers hjn can be provided, wherein a hidden layer 430 uses output values of another (hidden) layer 430 as input values. The nodes of a hidden layer 430 perform mathematical operations. Herein, an output value of a node hj corresponds to a non-linear function f of its input values xi and the weighting factors wi. After receiving input values xi, a node hj performs a summation of a multiplication of each input value xi weighted by weighting factors wi as determined by the following function:

h _(j) =f(Σ_(i) x _(i) ·w _(ij))

In particular, an output value of a node hj is formed as a function f of node activation, for example a sigmoid function or a linear ramp function. The output values hj are transmitted to the output node or nodes oj. Once again, summation of a weighted multiplication of each output value hj is calculated as a function of the node activation f:

o _(j) =f(Σ_(i) h _(i) ·w′ _(ij))

The neural network 400 shown here is a feedforward neural network, such as is preferably used for the first computational linguistics algorithm P1 in which all nodes 430 process the output values of a previous layer in the form of their weighted sum as input values. In particular, for the second computational linguistics algorithm, according to one or more example embodiments of the present invention, other neural network types can be used, for example a feedback neural network or for example a self-learning (also called recurrent) neural network, in which an output value of a node hj can simultaneously be its own input value.

The neural network 400 is preferably trained via a supervised training method in order to recognize patterns. One known approach is back-propagation, which can be applied in exemplary embodiments of the invention. During the training, the neural network 400 is applied to training input values and has to generate corresponding output values known in advance. Iteratively, mean square errors (“MSE”) between calculated and expected output values are calculated and individual weighting factors 420 are adjusted until the discrepancy between calculated and expected output values is below a predetermined threshold.

Where not explicitly illustrated, but advisable and in the spirit of the invention, individual exemplary embodiments, individual aspects or features thereof can be combined with one another or interchanged without departing from the scope of the present invention. Where transferrable, advantages of one or more example embodiments of the present invention described with reference to one exemplary embodiment also apply without explicit reference to other exemplary embodiments.

Example embodiments of the present invention enables the use of computational linguistics algorithms comprising neural networks for speech recognition and derivation of speech commands in safety-relevant applications, which must in particular be embodied as first-failure safe. Tests have proven that the described solution is more reliable than conventionally implemented speech recognition algorithms without a safety function. In some embodiments, the invention is characterized by scalability with respect to user friendliness and/or safety (failure detection). On the one hand, this can be used to safeguard speech commands of different safety levels appropriately in each case. On the other hand, it is possible to improve usability over time if experience has shown that speech command recognition or speech command verification in a defined target environment corresponds to desired safety specifications and sufficient reliability has been demonstrated. Alternatively, it is possible to increase safety if has been recognized that, for example due to special ambient conditions (for example background noise), reliable recognition of commands transmitted by speech input does not work sufficiently well.

Scalability generally enables a gradual change of resilience in terms of safety between conventionally implemented components and components implemented via methods of machine learning. This can create a migration path toward the use of computational linguistics algorithms comprising neural networks that is resilient in terms of safety.

Finally, reference is made to the fact that the embodiment of a verification mechanism according to the invention for control commands derived via speech recognition can be applied with respect to an incorrect interpretation of recognized commands (a user intention comprising speech input is assigned an incorrect speech command) or with respect to an untimely, i.e., too slow, recognition of speech commands. However, according to one or more example embodiments of the present invention, a failure with which no speech command is recognized with the first computational linguistics algorithm in a speech input despite its containing a user intention cannot be safeguarded. The present invention is, therefore, for example, not suitable for safeguarding an emergency-stop function.

It will be understood that, although the terms first, second, etc. may be used herein to describe various elements, components, regions, layers, and/or sections, these elements, components, regions, layers, and/or sections, should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element, without departing from the scope of example embodiments. As used herein, the term “and/or,” includes any and all combinations of one or more of the associated listed items. The phrase “at least one of” has the same meaning as “and/or”.

Spatially relative terms, such as “beneath,” “below,” “lower,” “under,” “above,” “upper,” and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “below,” “beneath,” or “under,” other elements or features would then be oriented “above” the other elements or features. Thus, the example terms “below” and “under” may encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly. In addition, when an element is referred to as being “between” two elements, the element may be the only element between the two elements, or one or more other intervening elements may be present.

Spatial and functional relationships between elements (for example, between modules) are described using various terms, including “on,” “connected,” “engaged,” “interfaced,” and “coupled.” Unless explicitly described as being “direct,” when a relationship between first and second elements is described in the disclosure, that relationship encompasses a direct relationship where no other intervening elements are present between the first and second elements, and also an indirect relationship where one or more intervening elements are present (either spatially or functionally) between the first and second elements. In contrast, when an element is referred to as being “directly” on, connected, engaged, interfaced, or coupled to another element, there are no intervening elements present. Other words used to describe the relationship between elements should be interpreted in a like fashion (e.g., “between,” versus “directly between,” “adjacent,” versus “directly adjacent,” etc.).

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments. As used herein, the singular forms “a,” “an,” and “the,” are intended to include the plural forms as well, unless the context clearly indicates otherwise. As used herein, the terms “and/or” and “at least one of” include any and all combinations of one or more of the associated listed items. It will be further understood that the terms “comprises,” “comprising,” “includes,” and/or “including,” when used herein, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. Expressions such as “at least one of,” when preceding a list of elements, modify the entire list of elements and do not modify the individual elements of the list. Also, the term “example” is intended to refer to an example or illustration.

It should also be noted that in some alternative implementations, the functions/acts noted may occur out of the order noted in the figures. For example, two figures shown in succession may in fact be executed substantially concurrently or may sometimes be executed in the reverse order, depending upon the functionality/acts involved.

Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which example embodiments belong. It will be further understood that terms, e.g., those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

It is noted that some example embodiments may be described with reference to acts and symbolic representations of operations (e.g., in the form of flow charts, flow diagrams, data flow diagrams, structure diagrams, block diagrams, etc.) that may be implemented in conjunction with units and/or devices discussed above. Although discussed in a particularly manner, a function or operation specified in a specific block may be performed differently from the flow specified in a flowchart, flow diagram, etc. For example, functions or operations illustrated as being performed serially in two consecutive blocks may actually be performed simultaneously, or in some cases be performed in reverse order. Although the flowcharts describe the operations as sequential processes, many of the operations may be performed in parallel, concurrently or simultaneously. In addition, the order of operations may be re-arranged. The processes may be terminated when their operations are completed, but may also have additional steps not included in the figure. The processes may correspond to methods, functions, procedures, subroutines, subprograms, etc.

Specific structural and functional details disclosed herein are merely representative for purposes of describing example embodiments. The present invention may, however, be embodied in many alternate forms and should not be construed as limited to only the embodiments set forth herein.

In addition, or alternative, to that discussed above, units and/or devices according to one or more example embodiments may be implemented using hardware, software, and/or a combination thereof. For example, hardware devices may be implemented using processing circuitry such as, but not limited to, a processor, Central Processing Unit (CPU), a controller, an arithmetic logic unit (ALU), a digital signal processor, a microcomputer, a field programmable gate array (FPGA), a System-on-Chip (SoC), a programmable logic unit, a microprocessor, or any other device capable of responding to and executing instructions in a defined manner. Portions of the example embodiments and corresponding detailed description may be presented in terms of software, or algorithms and symbolic representations of operation on data bits within a computer memory. These descriptions and representations are the ones by which those of ordinary skill in the art effectively convey the substance of their work to others of ordinary skill in the art. An algorithm, as the term is used here, and as it is used generally, is conceived to be a self-consistent sequence of steps leading to a desired result. The steps are those requiring physical manipulations of physical quantities. Usually, though not necessarily, these quantities take the form of optical, electrical, or magnetic signals capable of being stored, transferred, combined, compared, and otherwise manipulated. It has proven convenient at times, principally for reasons of common usage, to refer to these signals as bits, values, elements, symbols, characters, terms, numbers, or the like.

It should be borne in mind that all of these and similar terms are to be associated with the appropriate physical quantities and are merely convenient labels applied to these quantities. Unless specifically stated otherwise, or as is apparent from the discussion, terms such as “processing” or “computing” or “calculating” or “determining” of “displaying” or the like, refer to the action and processes of a computer system, or similar electronic computing device/hardware, that manipulates and transforms data represented as physical, electronic quantities within the computer system's registers and memories into other data similarly represented as physical quantities within the computer system memories or registers or other such information storage, transmission or display devices.

In this application, including the definitions below, the term ‘module’ or the term ‘controller’ may be replaced with the term ‘circuit.’ The term ‘module’ may refer to, be part of, or include processor hardware (shared, dedicated, or group) that executes code and memory hardware (shared, dedicated, or group) that stores code executed by the processor hardware.

The module may include one or more interface circuits. In some examples, the interface circuits may include wired or wireless interfaces that are connected to a local area network (LAN), the Internet, a wide area network (WAN), or combinations thereof. The functionality of any given module of the present disclosure may be distributed among multiple modules that are connected via interface circuits. For example, multiple modules may allow load balancing. In a further example, a server (also known as remote, or cloud) module may accomplish some functionality on behalf of a client module.

Software may include a computer program, program code, instructions, or some combination thereof, for independently or collectively instructing or configuring a hardware device to operate as desired. The computer program and/or program code may include program or computer-readable instructions, software components, software modules, data files, data structures, and/or the like, capable of being implemented by one or more hardware devices, such as one or more of the hardware devices mentioned above. Examples of program code include both machine code produced by a compiler and higher level program code that is executed using an interpreter.

For example, when a hardware device is a computer processing device (e.g., a processor, Central Processing Unit (CPU), a controller, an arithmetic logic unit (ALU), a digital signal processor, a microcomputer, a microprocessor, etc.), the computer processing device may be configured to carry out program code by performing arithmetical, logical, and input/output operations, according to the program code. Once the program code is loaded into a computer processing device, the computer processing device may be programmed to perform the program code, thereby transforming the computer processing device into a special purpose computer processing device. In a more specific example, when the program code is loaded into a processor, the processor becomes programmed to perform the program code and operations corresponding thereto, thereby transforming the processor into a special purpose processor.

Software and/or data may be embodied permanently or temporarily in any type of machine, component, physical or virtual equipment, or computer storage medium or device, capable of providing instructions or data to, or being interpreted by, a hardware device. The software also may be distributed over network coupled computer systems so that the software is stored and executed in a distributed fashion. In particular, for example, software and data may be stored by one or more computer readable recording mediums, including the tangible or non-transitory computer-readable storage media discussed herein.

Even further, any of the disclosed methods may be embodied in the form of a program or software. The program or software may be stored on a non-transitory computer readable medium and is adapted to perform any one of the aforementioned methods when run on a computer device (a device including a processor). Thus, the non-transitory, tangible computer readable medium, is adapted to store information and is adapted to interact with a data processing system or computer device to execute the program of any of the above mentioned embodiments and/or to perform the method of any of the above mentioned embodiments.

Example embodiments may be described with reference to acts and symbolic representations of operations (e.g., in the form of flow charts, flow diagrams, data flow diagrams, structure diagrams, block diagrams, etc.) that may be implemented in conjunction with units and/or devices discussed in more detail below. Although discussed in a particularly manner, a function or operation specified in a specific block may be performed differently from the flow specified in a flowchart, flow diagram, etc. For example, functions or operations illustrated as being performed serially in two consecutive blocks may actually be performed simultaneously, or in some cases be performed in reverse order.

According to one or more example embodiments, computer processing devices may be described as including various functional units that perform various operations and/or functions to increase the clarity of the description. However, computer processing devices are not intended to be limited to these functional units. For example, in one or more example embodiments, the various operations and/or functions of the functional units may be performed by other ones of the functional units. Further, the computer processing devices may perform the operations and/or functions of the various functional units without sub-dividing the operations and/or functions of the computer processing units into these various functional units.

Units and/or devices according to one or more example embodiments may also include one or more storage devices. The one or more storage devices may be tangible or non-transitory computer-readable storage media, such as random access memory (RAM), read only memory (ROM), a permanent mass storage device (such as a disk drive), solid state (e.g., NAND flash) device, and/or any other like data storage mechanism capable of storing and recording data. The one or more storage devices may be configured to store computer programs, program code, instructions, or some combination thereof, for one or more operating systems and/or for implementing the example embodiments described herein. The computer programs, program code, instructions, or some combination thereof, may also be loaded from a separate computer readable storage medium into the one or more storage devices and/or one or more computer processing devices using a drive mechanism. Such separate computer readable storage medium may include a Universal Serial Bus (USB) flash drive, a memory stick, a Blu-ray/DVD/CD-ROM drive, a memory card, and/or other like computer readable storage media. The computer programs, program code, instructions, or some combination thereof, may be loaded into the one or more storage devices and/or the one or more computer processing devices from a remote data storage device via a network interface, rather than via a local computer readable storage medium. Additionally, the computer programs, program code, instructions, or some combination thereof, may be loaded into the one or more storage devices and/or the one or more processors from a remote computing system that is configured to transfer and/or distribute the computer programs, program code, instructions, or some combination thereof, over a network. The remote computing system may transfer and/or distribute the computer programs, program code, instructions, or some combination thereof, via a wired interface, an air interface, and/or any other like medium.

The one or more hardware devices, the one or more storage devices, and/or the computer programs, program code, instructions, or some combination thereof, may be specially designed and constructed for the purposes of the example embodiments, or they may be known devices that are altered and/or modified for the purposes of example embodiments.

A hardware device, such as a computer processing device, may run an operating system (OS) and one or more software applications that run on the OS. The computer processing device also may access, store, manipulate, process, and create data in response to execution of the software. For simplicity, one or more example embodiments may be exemplified as a computer processing device or processor; however, one skilled in the art will appreciate that a hardware device may include multiple processing elements or processors and multiple types of processing elements or processors. For example, a hardware device may include multiple processors or a processor and a controller. In addition, other processing configurations are possible, such as parallel processors.

The computer programs include processor-executable instructions that are stored on at least one non-transitory computer-readable medium (memory). The computer programs may also include or rely on stored data. The computer programs may encompass a basic input/output system (BIOS) that interacts with hardware of the special purpose computer, device drivers that interact with particular devices of the special purpose computer, one or more operating systems, user applications, background services, background applications, etc. As such, the one or more processors may be configured to execute the processor executable instructions.

The computer programs may include: (i) descriptive text to be parsed, such as HTML (hypertext markup language) or XML (extensible markup language), (ii) assembly code, (iii) object code generated from source code by a compiler, (iv) source code for execution by an interpreter, (v) source code for compilation and execution by a just-in-time compiler, etc. As examples only, source code may be written using syntax from languages including C, C++, C#, Objective-C, Haskell, Go, SQL, R, Lisp, Java®, Fortran, Perl, Pascal, Curl, OCaml, Javascript®, HTML5, Ada, ASP (active server pages), PHP, Scala, Eiffel, Smalltalk, Erlang, Ruby, Flash®, Visual Basic®, Lua, and Python®.

Further, at least one example embodiment relates to the non-transitory computer-readable storage medium including electronically readable control information (processor executable instructions) stored thereon, configured in such that when the storage medium is used in a controller of a device, at least one embodiment of the method may be carried out.

The computer readable medium or storage medium may be a built-in medium installed inside a computer device main body or a removable medium arranged so that it can be separated from the computer device main body. The term computer-readable medium, as used herein, does not encompass transitory electrical or electromagnetic signals propagating through a medium (such as on a carrier wave); the term computer-readable medium is therefore considered tangible and non-transitory. Non-limiting examples of the non-transitory computer-readable medium include, but are not limited to, rewriteable non-volatile memory devices (including, for example flash memory devices, erasable programmable read-only memory devices, or a mask read-only memory devices); volatile memory devices (including, for example static random access memory devices or a dynamic random access memory devices); magnetic storage media (including, for example an analog or digital magnetic tape or a hard disk drive); and optical storage media (including, for example a CD, a DVD, or a Blu-ray Disc). Examples of the media with a built-in rewriteable non-volatile memory, include but are not limited to memory cards; and media with a built-in ROM, including but not limited to ROM cassettes; etc. Furthermore, various information regarding stored images, for example, property information, may be stored in any other form, or it may be provided in other ways.

The term code, as used above, may include software, firmware, and/or microcode, and may refer to programs, routines, functions, classes, data structures, and/or objects. Shared processor hardware encompasses a single microprocessor that executes some or all code from multiple modules. Group processor hardware encompasses a microprocessor that, in combination with additional microprocessors, executes some or all code from one or more modules. References to multiple microprocessors encompass multiple microprocessors on discrete dies, multiple microprocessors on a single die, multiple cores of a single microprocessor, multiple threads of a single microprocessor, or a combination of the above.

Shared memory hardware encompasses a single memory device that stores some or all code from multiple modules. Group memory hardware encompasses a memory device that, in combination with other memory devices, stores some or all code from one or more modules.

The term memory hardware is a subset of the term computer-readable medium. The term computer-readable medium, as used herein, does not encompass transitory electrical or electromagnetic signals propagating through a medium (such as on a carrier wave); the term computer-readable medium is therefore considered tangible and non-transitory. Non-limiting examples of the non-transitory computer-readable medium include, but are not limited to, rewriteable non-volatile memory devices (including, for example flash memory devices, erasable programmable read-only memory devices, or a mask read-only memory devices); volatile memory devices (including, for example static random access memory devices or a dynamic random access memory devices); magnetic storage media (including, for example an analog or digital magnetic tape or a hard disk drive); and optical storage media (including, for example a CD, a DVD, or a Blu-ray Disc). Examples of the media with a built-in rewriteable non-volatile memory, include but are not limited to memory cards; and media with a built-in ROM, including but not limited to ROM cassettes; etc. Furthermore, various information regarding stored images, for example, property information, may be stored in any other form, or it may be provided in other ways.

The apparatuses and methods described in this application may be partially or fully implemented by a special purpose computer created by configuring a general purpose computer to execute one or more particular functions embodied in computer programs. The functional blocks and flowchart elements described above serve as software specifications, which can be translated into the computer programs by the routine work of a skilled technician or programmer.

Although described with reference to specific examples and drawings, modifications, additions and substitutions of example embodiments may be variously made according to the description by those of ordinary skill in the art. For example, the described techniques may be performed in an order different with that of the methods described, and/or components such as the described system, architecture, devices, circuit, and the like, may be connected or combined to be different from the above-described methods, or results may be appropriately achieved by other components or equivalents. 

We claim:
 1. A method for speech control of a medical apparatus, the method comprising: capturing an audio signal containing operator speech input directed at controlling the apparatus; first analyzing the audio signal for a first speech analysis result; recognizing a first speech command based on the first speech analysis result; assigning the first speech command to a safety class, the safety class being provided for safety-critical speech commands; ascertaining a verification signal to confirm the first speech command; generating a control signal for controlling the medical apparatus, the generating being based on the first speech command and the verification signal, wherein the control signal is for controlling the medical apparatus according to the first speech command; and inputting the control signal into the medical apparatus.
 2. The method of claim 1, wherein the ascertaining the verification signal includes the first speech command and the method further comprises: issuing a prompt to confirm the first speech command to the operator.
 3. The method of claim 2, wherein the ascertaining the verification signal comprises: capturing user input directed at the confirmation of the first speech command from the operator.
 4. The method of claim 3, wherein at least one of: the outputting outputs an audio signal based on the speech command, or the capturing captures the user input as an audio signal.
 5. The method of claim 3, wherein the verification signal confirms the first speech command if the operator the user input satisfies at least one of: a predefined time criterion, or a predefined content criterion.
 6. The method of claim 5, wherein the time criterion is adjustable based on the first speech command.
 7. The method of claim 4, wherein the ascertaining the verification signal comprises: outputting a prompt for the user input to the operator and capturing the user input, the user input comprising the speech control information.
 8. The method of claim 1, wherein the first analyzing comprises: applying a first computational linguistics algorithm, the first computation linguistics algorithm comprising a first trained function to the audio signal.
 9. The method of claim 1, wherein the ascertaining the verification signal comprises: analyzing the audio signal to provide a second speech analysis result, recognizing a second speech command based on the second speech analysis result, and comparing the first and second speech command, wherein the verification signal confirms the first speech command if the first speech command and the second speech command satisfy a conformity criterion.
 10. The method of claim 8, wherein the first analyzing comprises: applying a second computational linguistics algorithm, the second computational linguistics algorithm comprising a second trained function to the audio signal, wherein the first trained function and the second trained function are different from one another.
 11. The method of claim 10, wherein the second trained function is configured only to identify safety-critical speech commands in the audio signal.
 12. The method of claim 1, wherein the first analyzing the audio signal comprises at least one of: tokenizing for at least one of segmenting letters, words or sentences within the audio signal, and at least one of the first speech command or the second speech command are recognized based on at least one of first tokenization information or second tokenization information, or recognizing semantic analysis of the audio signal and the first speech command and the second speech command are recognized based on first semantic information and second semantic information.
 13. A speech control apparatus for speech control of a medical apparatus comprising: at least one first interface configured to capture an audio signal containing operator speech input directed at controlling the apparatus; at least one evaluation unit configured to analyze the audio signal and provide a first speech analysis result, recognize a first speech command based on the first speech analysis result, assign the first speech command to a safety class, wherein a safety class is provided for safety-critical speech commands, ascertain a verification signal to confirm the first speech command; a control unit configured to generate a control signal for controlling the medical apparatus based on the first speech command and the verification signal provided that the first speech command has been based on the verification signal, wherein the control signal is suitable for controlling the medical apparatus according to the first speech command; and a second interface configured to input the control signal into the medical apparatus.
 14. A medical system comprising: the speech control apparatus of claim 13; and the medical apparatus, the medical apparatus configured to perform a medical procedure.
 15. A non-transitory computer program product, which comprises a program and can be loaded directly into a memory of a programmable computing unit, with program means for executing the method of claim 1 when the program is executed.
 16. A non-transitory computer-readable storage medium storing readable and executable program that, when executed by a programmable computing unit, cause the programmable computing unit to perform the method of claim
 1. 17. The method of claim 2, wherein the first analyzing comprises: applying a first computational linguistics algorithm, the first computation linguistics algorithm comprising a first trained function to the audio signal.
 18. The method of claim 3, wherein the ascertaining the verification signal comprises: analyzing the audio signal to provide a second speech analysis result, recognizing a second speech command based on the second speech analysis result, and comparing the first and second speech command, wherein the verification signal confirms the first speech command if the first speech command and the second speech command satisfy a conformity criterion.
 19. The method of claim 3, wherein the first analyzing comprises: applying a first computational linguistics algorithm, the first computation linguistics algorithm comprising a first trained function to the audio signal.
 20. The method of claim 3, wherein the ascertaining the verification signal comprises: analyzing the audio signal to provide a second speech analysis result, recognizing a second speech command based on the second speech analysis result, and comparing the first and second speech command, wherein the verification signal confirms the first speech command if the first speech command and the second speech command satisfy a conformity criterion. 